In computing , the clock rate or clock speed typically refers to the frequency at which the clock generator of a processor can generate pulses , which are used to synchronize the operations of its components, and is used as an indicator of the processor's speed. It is measured in the SI unit of frequency hertz (Hz).
123-723: Xeon ( / ˈ z iː ɒ n / ; ZEE -on ) is a brand of x86 microprocessors designed, manufactured, and marketed by Intel , targeted at the non-consumer workstation , server , and embedded markets. It was introduced in June 1998. Xeon processors are based on the same architecture as regular desktop-grade CPUs, but have advanced features such as support for error correction code (ECC) memory , higher core counts, more PCI Express lanes, support for larger amounts of RAM, larger cache memory and extra provision for enterprise-grade reliability, availability and serviceability (RAS) features responsible for handling hardware exceptions through
246-535: A 45 nm process . The models are the X3320, X3330, X3350, X3360, X3370 and X3380, being rebadged Q9300, Q9400, Q9450, Q9550, Q9650, QX9770, running at 2.50 GHz, 2.66 GHz, 2.66 GHz, 2.83 GHz, 3.0 GHz, and 3.16 GHz, respectively. The L2 cache is a unified 6 MB per die (except for the X3320 and X3330 with a smaller 3 MB L2 cache per die), and a front-side bus of 1333 MHz. All models feature Intel 64 (Intel's x86-64 implementation),
369-618: A 64 KB (one segment) stack in memory supported by computer hardware . Only words (two bytes) can be pushed to the stack. The stack grows toward numerically lower addresses, with SS:SP pointing to the most recently pushed item. There are 256 interrupts , which can be invoked by both hardware and software. The interrupts can cascade, using the stack to store the return address . The original Intel 8086 and 8088 have fourteen 16- bit registers. Four of them (AX, BX, CX, DX) are general-purpose registers (GPRs), although each may have an additional purpose; for example, only CX can be used as
492-579: A backward compatible version of this functionality on the same microprocessor as the main processor. In addition to this, modern x86 designs also contain a SIMD -unit (see SSE below) where instructions can work in parallel on (one or two) 128-bit words, each containing two or four floating-point numbers (each 64 or 32 bits wide respectively), or alternatively, 2, 4, 8 or 16 integers (each 64, 32, 16 or 8 bits wide respectively). The presence of wide SIMD registers means that existing x86 processors can load or store up to 128 bits of memory data in
615-450: A "cumulative clock rate" measure is sometimes assumed by taking the total cores and multiplying by the total clock rate (e.g. a dual-core 2.8 GHz processor running at a cumulative 5.6 GHz). There are many other factors to consider when comparing the performance of CPUs, like the width of the CPU's data bus , the latency of the memory, and the cache architecture. The clock rate alone
738-604: A 1.07 GT/s FSB , fits into the Tigerton's mPGA604 socket, and is compatible with both the Intel Caneland and IBM X4 chipsets. These processors support DDR2-1066 (533 MHz), and have a maximum TDP below 130 W. They are intended for blades and other stacked computer systems. Availability was scheduled for the second half of 2008. It was followed shortly by the Nehalem microarchitecture . Total transistor count
861-604: A 1066 MT/s FSB, and an ending of -5 implies a 1333 MT/s FSB. All models have a TDP of 80 W with the exception of the X5355, which has a TDP of 120 W, and the X5365, which has a TDP of 150 W. A low-voltage version of Clovertown with a TDP of 50 W has a model numbers L5310, L5320 and L5335 (1.6 GHz, 1.86 GHz and 2.0 GHz respectively). The 3.0 GHz X5365 arrived in July 2007, and became available in
984-441: A 1066 MT/s FSB, and higher models use a 1333 MT/s FSB. Intel released Clovertown , product code 80563, on November 14, 2006 with models E5310, E5320, E5335, E5345, and X5355, ranging from 1.6 GHz to 2.66 GHz. All models support MMX, SSE, SSE2, SSE3, SSSE3, Intel 64, XD bit (an NX bit implementation), Intel VT . The E and X designations are borrowed from Intel's Core 2 model numbering scheme; an ending of -0 implies
1107-422: A 1066 MT/s FSB. Dempsey has 4 MB of L2 cache (2 MB per core). A Medium Voltage model, at 3.2 GHz and 1066 MT/s FSB (model number 5063), has also been released. Dempsey also introduces a new interface for Xeon processors: LGA 771 , also known as Socket J . Dempsey was the first Xeon core in a long time to be somewhat competitive with its Opteron-based counterparts, although it could not claim
1230-425: A 1333 MT/s front-side bus, support Enhanced Intel SpeedStep Technology and Intel Virtualization Technology but do not support Hyper-Threading. On June 26, 2006, Intel released the dual-core CPU (Xeon branded 5100 series) codenamed Woodcrest (product code 80556); it was the first Intel Core/Merom microarchitecture processor to be launched on the market. It is a dual-processor server and workstation version of
1353-550: A 2 MB configuration: four SRAMs on both sides of the PCB. Each SRAM was a 12.90 mm by 17.23 mm (222.21 mm) die fabricated in a 0.35 μm four-layer metal CMOS process and packaged in a cavity-down wire-bonded land grid array (LGA). The additional cache required a larger module and thus the Pentium II Xeon used a larger slot, Slot 2 . It was supported by the i440GX dual-processor workstation chipset and
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#17327763372151476-601: A 512 kB L2 cache. This was based on the " Northwood " Pentium 4 core. A new server chipset, E7500 (which allowed the use of dual-channel DDR SDRAM ), was released to support this processor in servers, and soon the bus speed was boosted to 533 MT/s (accompanied by a new socket and two new chipsets: the E7501 for servers and the E7505 for workstations). The Prestonia performed much better than its predecessor and noticeably better than Athlon MP. The support of new features in
1599-565: A TDP of 65 W. The 5160 has a TDP of 80 W and the 5148LV (2.33 GHz) has a TDP of 40 W. The previous generation Xeons had a TDP of 130 W. All models support Intel 64 (Intel's x86-64 implementation), the XD bit , and Virtualization Technology , with the Demand-based switching power management option only on Dual-Core Xeon 5140 or above. Woodcrest has 4 MB of shared L2 cache. On November 11, 2007, Intel released
1722-539: A counter with the loop instruction. Each can be accessed as two separate bytes (thus BX's high byte can be accessed as BH and low byte as BL). Two pointer registers have special roles: SP (stack pointer) points to the "top" of the stack , and BP (base pointer) is often used to point at some other place in the stack, typically above the local variables (see frame pointer ). The registers SI, DI, BX and BP are address registers , and may also be used for array indexing. One of four possible 'segment registers' (CS, DS, SS and ES)
1845-532: A decisive lead in any performance metric – that would have to wait for its successor, the Woodcrest. On March 14, 2006, Intel released a dual-core processor codenamed Sossaman and branded as Xeon LV (low-voltage). Subsequently, an ULV (ultra-low-voltage) version was released. The Sossaman was a low-/ultra-low-power and double-processor capable CPU (like AMD Quad FX ), based on the " Yonah " processor, for ultradense non-consumer environment (i.e., targeted at
1968-499: A discrete graphics card or a separate GPU if computer monitor output is desired. Intel Xeon is a distinct product line from the similarly named Intel Xeon Phi . The first-generation Xeon Phi is a completely different type of device more comparable to a graphics card; it is designed for a PCI Express slot and is meant to be used as a multi-core coprocessor, like the Nvidia Tesla . In the second generation, Xeon Phi evolved into
2091-424: A kind of system-level prefix. An 8086 system, including coprocessors such as 8087 and 8089 , and simpler Intel-specific system chips, was thereby described as an iAPX 86 system. There were also terms iRMX (for operating systems), iSBC (for single-board computers), and iSBX (for multimodule boards based on the 8086-architecture), all together under the heading Microsystem 80 . However, this naming scheme
2214-667: A little more quickly or use slightly less energy per transition, pushing back those limits, producing new CPUs that can run at slightly higher clock rates. The ultimate limits to energy per transition are explored in reversible computing . The first fully reversible CPU, the Pendulum, was implemented using standard CMOS transistors in the late 1990s at the Massachusetts Institute of Technology. Engineers also continue to find new ways to design CPUs so that they complete more instructions per clock cycle, thus achieving
2337-430: A lower CPI (cycles or clock cycles per instruction) count, although they may run at the same or a lower clock rate as older CPUs. This is achieved through architectural techniques such as instruction pipelining and out-of-order execution which attempts to exploit instruction level parallelism in the code. The clock rate of a CPU is most useful for providing comparisons between CPUs in the same family. The clock rate
2460-418: A lowest common denominator for many modern operating systems and also probably because the term became common after the introduction of the 80386 in 1985. A few years after the introduction of the 8086 and 8088, Intel added some complexity to its naming scheme and terminology as the "iAPX" of the ambitious but ill-fated Intel iAPX 432 processor was tried on the more successful 8086 family of chips, applied as
2583-640: A main processor more similar to the Xeon. It conforms to the same socket as a Xeon processor and is x86-compatible; however, as compared to Xeon, the design point of the Xeon Phi emphasizes more cores with higher memory bandwidth. The first Xeon-branded processor was the Pentium II Xeon (code-named " Drake "). It was released in 1998, replacing the Pentium Pro in Intel's high-end server lineup. The Pentium II Xeon
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#17327763372152706-476: A major change to the architecture referred to as X86S (formerly known as X86-S). The S in X86S stands for "simplification", which aims to remove support for legacy execution modes and instructions. A processor implementing this proposal would start execution directly in long mode and would only support 64-bit operating systems. 32-bit code would only be supported for user applications running in ring 3, and would use
2829-547: A memory location. However, this memory operand may also be the destination (or a combined source and destination), while the other operand, the source, can be either register or immediate. Among other factors, this contributes to a code size that rivals eight-bit machines and enables efficient use of instruction cache memory. The relatively small number of general registers (also inherited from its 8-bit ancestors) has made register-relative addressing (using small immediate offsets) an important method of accessing operands, especially on
2952-560: A more complex micro-op which fits the execution model better and thus can be executed faster or with fewer machine resources involved. Another way to try to improve performance is to cache the decoded micro-operations, so the processor can directly access the decoded micro-operations from a special cache, instead of decoding them again. Intel followed this approach with the Execution Trace Cache feature in their NetBurst microarchitecture (for Pentium 4 processors) and later in
3075-440: A number ending in "5" have a 1333 MT/s FSB. The 3100 series, codenamed Wolfdale (product code 80570) dual-core Xeon (branded) CPU, was just a rebranded version of the Intel's mainstream Core 2 Duo E7000/E8000 and Pentium Dual-Core E5000 processors, featuring the same 45 nm process and 6 MB of L2 cache. Unlike most Xeon processors, they only support single-CPU operation. They use LGA 775 (Socket T), operate on
3198-583: A point to point interface allowing the full front side bus bandwidth per processor. The 7xxx series is aimed at the large server market, supporting configurations of up to 32 CPUs per host. Dunnington – the last CPU of the Penryn generation and Intel's first multi-core (above two) die – features a single-die six- (or hexa- ) core design with three unified 3 MB L2 caches (resembling three merged 45 nm dual-core Wolfdale-3M dies), and 96 kB L1 cache (Data) and 16 MB of L3 cache. It features
3321-670: A single instruction and also perform bitwise operations (although not integer arithmetic ) on full 128-bits quantities in parallel. Intel's Sandy Bridge processors added the Advanced Vector Extensions (AVX) instructions, widening the SIMD registers to 256 bits. The Intel Initial Many Core Instructions implemented by the Knights Corner Xeon Phi processors, and the AVX-512 instructions implemented by
3444-651: A socketable form factor. Xeon D was introduced to compete with emerging ARM hyperscale server solutions that offered greater multi-threaded performance and power effiency. Xeon W branding is used for Xeon workstation processors. It was first introduced in August 2017 with the release of the Skylake -based Xeon W-2100 series workstation processors. With Sapphire Rapids-WS workstation processors that launched in March 2023, Intel introduced tiers within Xeon W. Xeon w3, w5, w7 and w9
3567-709: Is 1.9 billion. Announced on September 15, 2008. Xeon 3400-series processors based on Lynnfield are designed for entry-level servers compared to Bloomfield, which is designed for uniprocessor workstations. Like Bloomfield, they are quad-core single-package processors based on the Nehalem microarchitecture , but were introduced almost a year later, in September 2009. The same processors are marketed for mid-range to high-end desktops systems as Core i5 and Core i7 . They have two integrated memory channels as well as PCI Express and Direct Media Interface (DMI) links, but no QuickPath Interconnect (QPI) interface. At low end of
3690-552: Is 120 W TDP or above. The speed of 3.00 GHz comes as four models, two models with 80 W TDP two other models with 120 W TDP with 1333 MHz or 1600 MHz front-side bus respectively. The fastest Harpertown is the X5492 whose TDP of 150 W is higher than those of the Prescott-based Xeon DP but having twice as many cores. (The X5482 is also sold under the name "Core 2 Extreme QX9775" for use in
3813-527: Is a four-socket (packaged in Socket 604 ) and more capable quad-core processor , consisting of two dual core Core 2 architecture silicon chips on a single ceramic module, similar to Intel's Xeon 5300 series Clovertown processor modules. The 7300 series uses Intel's Caneland (Clarksboro) platform. Intel claims the 7300 series Xeons offer more than twice the performance per watt as Intel's previous generation 7100 series. The 7300 series' Caneland chipset provides
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3936-470: Is allowed for almost all instructions. The largest native size for integer arithmetic and memory addresses (or offsets ) is 16, 32 or 64 bits depending on architecture generation (newer processors include direct support for smaller integers as well). Multiple scalar values can be handled simultaneously via the SIMD unit present in later generations, as described below. Immediate addressing offsets and immediate data may be expressed as 8-bit quantities for
4059-626: Is almost identical to AMD64 ) in the 90 nm version of the Pentium 4 (" Prescott "), and a Xeon version codenamed " Nocona " with 1 MB L2 cache was released in 2004. Released with it were the E7525 (workstation), E7520 and E7320 (both server) chipsets, which added support for PCI Express 1.0a , DDR2 and Serial ATA 1.0a . The Xeon was noticeably slower than AMD's Opteron, although it could be faster in situations where Hyper-Threading came into play. A slightly updated core called " Irwindale "
4182-555: Is an MP-capable processor, similar to the 7300 series, but, in contrast, there is a single dual-core die. Intel released rebranded versions of its quad-core (2×2) Core 2 Quad processor as the Xeon 3200-series (product code 80562) on January 7, 2007. The 2 × 2 "quad-core" (dual-die dual-core) comprised two separate dual-core die next to each other in one CPU package. The models are the X3210, X3220 and X3230, running at 2.13 GHz, 2.4 GHz and 2.66 GHz, respectively. Like
4305-401: Is generally considered to be an inaccurate measure of performance when comparing different CPUs families. Software benchmarks are more useful. Clock rates can sometimes be misleading since the amount of work different CPUs can do in one cycle varies. For example, superscalar processors can execute more than one instruction per cycle (on average), yet it is not uncommon for them to do "less" in
4428-571: Is not synonymous with IBM PC compatibility , as this implies a multitude of other computer hardware . Embedded systems and general-purpose computers used x86 chips before the PC-compatible market started , some of them before the IBM PC (1981) debut. As of June 2022 , most desktop and laptop computers sold are based on the x86 architecture family, while mobile categories such as smartphones or tablets are dominated by ARM . At
4551-463: Is one of the two modes only available in long mode . The addressing modes were not dramatically changed from 32-bit mode, except that addressing was extended to 64 bits, virtual addresses are now sign extended to 64 bits (in order to disallow mode bits in virtual addresses), and other selector details were dramatically reduced. In addition, an addressing mode was added to allow memory references relative to RIP (the instruction pointer ), to ease
4674-476: Is only one of several factors that can influence performance when comparing processors in different families. For example, an IBM PC with an Intel 80486 CPU running at 50 MHz will be about twice as fast (internally only) as one with the same CPU and memory running at 25 MHz, while the same will not be true for MIPS R4000 running at the same clock rate as the two are different processors that implement different architectures and microarchitectures. Further,
4797-454: Is the server version for single CPU systems. This is a single-socket Intel Xeon processor designed for uniprocessor workstations. The performance improvements over the previous Xeon 3300 series are based mainly on: Gainestown or Nehalem-EP (Efficient Performance), the successor to Wolfdale-DP, and Harpertown, is based on the Nehalem microarchitecture and uses the same 45 nm manufacturing methods. The first processor released with
4920-1001: Is underlining x86 as an example of how continuous refinement of established industry standards can resist the competition from completely new architectures. The table below lists processor models and model series implementing various architectures in the x86 family, in chronological order. Each line item is characterized by significantly improved or commercially successful processor microarchitecture designs. At various times, companies such as IBM , VIA , NEC , AMD , TI , STM , Fujitsu , OKI , Siemens , Cyrix , Intersil , C&T , NexGen , UMC , and DM&P started to design or manufacture x86 processors (CPUs) intended for personal computers and embedded systems. Other companies that designed or manufactured x86 or x87 processors include ITT Corporation , National Semiconductor , ULSI System Technology, and Weitek . Such x86 implementations were seldom simple copies but often employed different internal microarchitectures and different solutions at
5043-491: Is used to form a memory address. In the original 8086 / 8088 / 80186 / 80188 every address was built from a segment register and one of the general purpose registers. For example ds:si is the notation for an address formed as [16 * ds + si] to allow 20-bit addressing rather than 16 bits, although this changed in later processors. At that time only certain combinations were supported. The FLAGS register contains flags such as carry flag , overflow flag and zero flag . Finally,
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5166-593: Is used. The first fully mechanical analog computer, the Z1 , operated at 1 Hz (cycle per second) clock frequency and the first electromechanical general purpose computer, the Z3 , operated at a frequency of about 5–10 Hz. The first electronic general purpose computer, the ENIAC , used a 100 kHz clock in its cycling unit. As each instruction took 20 cycles, it had an instruction rate of 5 kHz. The first commercial PC,
5289-458: The fstsw instruction, and it is common to simply use some of its bits for branching by copying it into the normal FLAGS. In the Intel 80286 , to support protected mode , three special registers hold descriptor table addresses (GDTR, LDTR, IDTR ), and a fourth task register (TR) is used for task switching. The 80287 is the floating-point coprocessor for the 80286 and has the same registers as
5412-470: The 6x86 was significantly faster than the Pentium on integer code. AMD later managed to grow into a serious contender with the K6 set of processors, which gave way to the very successful Athlon and Opteron . There were also other contenders, such as Centaur Technology (formerly IDT ), Rise Technology , and Transmeta . VIA Technologies ' energy efficient C3 and C7 processors, which were designed by
5535-496: The 80486 and all subsequent x86 models, the floating-point processing unit (FPU) is integrated on-chip. The Pentium MMX added eight 64-bit MMX integer vector registers (MM0 to MM7, which share lower bits with the 80-bit-wide FPU stack). With the Pentium III , Intel added a 32-bit Streaming SIMD Extensions (SSE) control/status register (MXCSR) and eight 128-bit SSE floating-point registers (XMM0 to XMM7). Starting with
5658-466: The 8088 . The 8086 was introduced in 1978 as a fully 16-bit extension of 8-bit Intel's 8080 microprocessor, with memory segmentation as a solution for addressing more memory than can be covered by a plain 16-bit address. The term "x86" came into being because the names of several successors to Intel's 8086 processor end in "86", including the 80186 , 80286 , 80386 and 80486 . Colloquially, their names were "186", "286", "386" and "486". The term
5781-573: The AMD Opteron processor, the x86 architecture extended the 32-bit registers into 64-bit registers in a way similar to how the 16 to 32-bit extension took place. An R -prefix (for "register") identifies the 64-bit registers (RAX, RBX, RCX, RDX, RSI, RDI, RBP, RSP, RFLAGS, RIP), and eight additional 64-bit general registers (R8–R15) were also introduced in the creation of x86-64 . Also, eight more SSE vector registers (XMM8–XMM15) were added. However, these extensions are only usable in 64-bit mode, which
5904-625: The Altair 8800 (by MITS), used an Intel 8080 CPU with a clock rate of 2 MHz (2 million cycles per second). The original IBM PC (c. 1981) had a clock rate of 4.77 MHz (4,772,727 cycles per second). In 1992, both Hewlett-Packard and Digital Equipment Corporation (DEC) exceeded 100 MHz with RISC techniques in the PA-7100 and AXP 21064 DEC Alpha respectively. In 1995, Intel's P5 Pentium chip ran at 100 MHz (100 million cycles per second). On March 6, 2000, AMD demonstrated passing
6027-572: The Apple Mac Pro on April 4, 2007. The X5365 performs up to around 38 GFLOPS in the LINPACK benchmark. On November 11, 2007 Intel presented Yorkfield -based Xeons – called Harpertown (product code 80574) – to the public. This family consists of dual die quad-core CPUs manufactured on a 45 nm process and featuring 1066 MHz, 1333 MHz, 1600 MHz front-side buses, with TDP rated from 40 W to 150 W depending on
6150-653: The Centaur company, were sold for many years following their release in 2005. Centaur's 2008 design, the VIA Nano , was their first processor with superscalar and speculative execution . It was introduced at about the same time (in 2008) as Intel introduced the Intel Atom , its first "in-order" processor after the P5 Pentium . Many additions and extensions have been added to the original x86 instruction set over
6273-517: The Core 2 processor. Intel claimed that it provides an 80% boost in performance, while reducing power consumption by 20% relative to the 5000 series Dempsey . Most models have a 1333 MT/s FSB, except for the 5110 and 5120, which have a 1066 MT/s FSB. The fastest processor (5160) operates at 3.0 GHz. All Woodcrest processors use the LGA 771 (Socket J) socket and all except two models have
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#17327763372156396-633: The Guinness World Record for the highest CPU clock rate is 8.42938 GHz with an overclocked AMD FX-8150 Bulldozer -based chip in an LHe / LN2 cryobath, 5 GHz on air . This is surpassed by the CPU-Z overclocking record for the highest CPU clock rate at 8.79433 GHz with an AMD FX-8350 Piledriver -based chip bathed in LN2 , achieved in November 2012. It is also surpassed by
6519-514: The Intel 8800 ), the Intel 960 , Intel 860 and the Intel/Hewlett-Packard Itanium architecture. However, the continuous refinement of x86 microarchitectures , circuitry and semiconductor manufacturing would make it hard to replace x86 in many segments. AMD's 64-bit extension of x86 (which Intel eventually responded to with a compatible design) and the scalability of x86 chips in the form of modern multi-core CPUs,
6642-492: The Intel Skulltrail system.) Intel 1.6 GT/s front-side bus Xeon processors will drop into the Intel 5400 (Seaburg) chipset whereas several mainboards featuring the Intel 5000/5200-chipset are enabled to run the processors with a 1333 MHz front-side bus speed. Seaburg features support for dual PCIe 2.0 x16 slots and up to 128 GB of memory. The 7300 series, codenamed Tigerton QC (product code 80565)
6765-702: The Machine Check Architecture (MCA). They are often capable of safely continuing execution where a normal processor cannot due to these extra RAS features, depending on the type and severity of the machine-check exception (MCE). Some also support multi-socket systems with two, four, or eight sockets through use of the Ultra Path Interconnect (UPI) bus, which replaced the older QuickPath Interconnect (QPI) bus. The Xeon brand has been maintained over several generations of IA-32 and x86-64 processors. The P6-based models added
6888-552: The Pentium D branded " Smithfield ") with 4 MB of L2 cache (2 MB per core). The only Paxville DP model released ran at 2.8 GHz, featured an 800 MT/s front side bus, and was produced using a 90 nm process . An MP-capable version of Paxville, codenamed Paxville MP , product code 80560, was released on November 1, 2005. There are two versions: one with 2 MB of L2 cache (1 MB per core), and one with 4 MB of L2 (2 MB per core). Paxville MP, called
7011-532: The TOP500 list. A large amount of software , including a large list of x86 operating systems are using x86-based hardware. Modern x86 is relatively uncommon in embedded systems , however, and small low power applications (using tiny batteries), and low-cost microprocessor markets, such as home appliances and toys, lack significant x86 presence. Simple 8- and 16-bit based architectures are common here, as well as simpler RISC architectures like RISC-V , although
7134-437: The XD bit , and Virtualization Technology , as well as Demand-based switching . The Yorkfield-CL (product code 80584) variant of these processors are X3323, X3353 and X3363. They have a reduced TDP of 80W and are made for single-CPU LGA 771 systems instead of LGA 775 , which is used in all other Yorkfield processors. In all other respects, they are identical to their Yorkfield counterparts. A quad-core (2×2) successor of
7257-662: The Xeon moniker to the end of the name of their corresponding desktop processor, but all models since 2001 used the name Xeon on its own. The Xeon CPUs generally have more cache and cores than their desktop counterparts in addition to multiprocessing capabilities. The Xeon Scalable brand for high-performance server was introduced in May 2017 with the Skylake-based Xeon Platinum 8100 series. Xeon Scalable processors range from dual socket to 8 socket support. Within
7380-773: The i450NX quad- or octo-processor server chipset. In 1999, the Pentium II Xeon was replaced by the Pentium III Xeon. Reflecting the incremental changes from the Pentium II " Deschutes " core to the Pentium III " Katmai " core, the first Pentium III Xeon, named " Tanner ", was just like its predecessor except for the addition of Streaming SIMD Extensions (SSE) and a few cache controller improvements. The product codes for Tanner mirrored that of Katmai ; 80525. The second version, named " Cascades ",
7503-461: The machine code format was expanded. To provide backward compatibility, segments with executable code can be marked as containing either 16-bit or 32-bit instructions. Special prefixes allow inclusion of 32-bit instructions in a 16-bit segment or vice versa. The 80386 had an optional floating-point coprocessor, the 80387 ; it had eight 80-bit wide registers: st(0) to st(7), like the 8087 and 80287. The 80386 could also use an 80287 coprocessor. With
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#17327763372157626-423: The 1 GHz milestone a few days ahead of Intel shipping 1 GHz in systems. In 2002, an Intel Pentium 4 model was introduced as the first CPU with a clock rate of 3 GHz (three billion cycles per second corresponding to ~ 0.33 nanoseconds per cycle). Since then, the clock rate of production processors has increased more slowly, with performance improvements coming from other design changes. Set in 2011,
7749-460: The 130 nm process allowed Intel to create the Xeon MP branded Gallatin with 4 MB cache. The Xeon branded Prestonia and Gallatin were designated 80532, like Northwood. Due to a lack of success with Intel's Itanium and Itanium 2 processors, AMD was able to introduce x86-64 , a 64-bit extension to the x86 architecture . Intel followed suit by including Intel 64 (formerly EM64T; it
7872-555: The 3000-series, these models only support single-CPU operation and operate on a 1066 MT/s front-side bus. It is targeted at the "blade" market. The X3220 is also branded and sold as Core2 Quad Q6600 , the X3230 as Q6700. Intel released relabeled versions of its quad-core Core 2 Quad Yorkfield Q9300, Q9400, Q9x50 and QX9770 processors as the Xeon 3300-series (product code 80569). This processor comprises two separate dual-core dies next to each other in one CPU package and manufactured in
7995-578: The 3400-series is not a Lynnfield but a Clarkdale processor, which is also used in the Core i3-500 and Core i5-600 processors as well as the Celeron G1000 and G6000 Pentium series. A single model was released in March 2010, the Xeon L3406. Compared to all other Clarkdale-based products, this one does not support integrated graphics, but has a much lower thermal design power of just 30 W. Compared to
8118-471: The 8087 with the same data formats. With the advent of the 32-bit 80386 processor, the 16-bit general-purpose registers, base registers, index registers, instruction pointer, and FLAGS register , but not the segment registers, were expanded to 32 bits. The nomenclature represented this by prefixing an " E " (for "extended") to the register names in x86 assembly language . Thus, the AX register corresponds to
8241-471: The CPU. Conversely, some people try to increase performance of a CPU by replacing the oscillator crystal with a higher frequency crystal (" overclocking "). However, the amount of overclocking is limited by the time for the CPU to settle after each pulse, and by the extra heat created. After each clock pulse, the signal lines inside the CPU need time to settle to their new state. That is, every signal line must finish transitioning from 0 to 1, or from 1 to 0. If
8364-585: The Decoded Stream Buffer (for Core-branded processors since Sandy Bridge). Transmeta used a completely different method in their Crusoe x86 compatible CPUs. They used just-in-time translation to convert x86 instructions to the CPU's native VLIW instruction set. Transmeta argued that their approach allows for more power efficient designs since the CPU can forgo the complicated decode step of more traditional x86 implementations. Addressing modes for 16-bit processor modes can be summarized by
8487-493: The Dual-Core Xeon 5000-series, Dempsey is a NetBurst microarchitecture processor produced using a 65 nm process , and is virtually identical to Intel's " Presler " Pentium Extreme Edition , except for the addition of SMP support, which lets Dempsey operate in dual-processor systems. Dempsey ranges between 2.50 GHz and 3.73 GHz (model numbers 5020–5080). Some models have a 667 MT/s FSB, and others have
8610-579: The E75xx series also gave it a key advantage over the Pentium III Xeon and Athlon MP branded CPUs (both stuck with rather old chipsets), and it quickly became the top-selling server/workstation processor. Subsequent to the Prestonia was the " Gallatin ", which had an L3 cache of 1 MB or 2 MB. Its Xeon MP version, which succeeded Foster MP , was popular in servers. Later experience with
8733-482: The Jackson Hyper-Threading capacity. This improved performance slightly, but not enough to lift it out of third place. It was also priced much higher than the dual-processor (DP) versions. The Foster shared the 80528 product code with Willamette. In 2002 Intel released a 130 nm version of Xeon branded CPU, codenamed " Prestonia ". It supported Intel's new Hyper-Threading technology and had
8856-877: The Knights Landing Xeon Phi processors and by Skylake-X processors, use 512-bit wide SIMD registers. During execution , current x86 processors employ a few extra decoding steps to split most instructions into smaller pieces called micro-operations. These are then handed to a control unit that buffers and schedules them in compliance with x86-semantics so that they can be executed, partly in parallel, by one of several (more or less specialized) execution units . These modern x86 designs are thus pipelined , superscalar , and also capable of out of order and speculative execution (via branch prediction , register renaming , and memory dependence prediction ), which means they may execute multiple (partial or complete) x86 instructions simultaneously, and not necessarily in
8979-535: The Lynnfield-based Xeon 3400 models, it only offers two cores. Bloomfield (or Nehalem-E ) is the codename for the successor to the Xeon 3300 series, is based on the Nehalem microarchitecture and uses the same 45 nm manufacturing methods as Intel's Penryn . The first processor released with the Nehalem architecture is the high-end desktop Core i7 , which was released in November 2008. This
9102-508: The Nehalem microarchitecture is the high-end desktop Core i7 , which was released in November 2008. Server processors of the Xeon 55xx range were first supplied to testers in December 2008. X86 x86 (also known as 80x86 or the 8086 family ) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the 8086 microprocessor and its 8-bit-external-bus variant,
9225-411: The Woodcrest for DP segment, consisting of two dual-core Woodcrest chips in one package similarly to the dual-core Pentium D branded CPUs (two single-core chips) or the quad-core Kentsfield . All Clovertowns use the LGA 771 package. The Clovertown has been usually implemented with two Woodcrest dies on a multi-chip module , with 8 MB of L2 cache (4 MB per die). Like Woodcrest, lower models use
9348-501: The Xeon 6 6700E line is an all E core based (Sierra Forest) line of processors. Xeon D is targeted towards microserver and edge computing markets with lower power consumption and integrated I/O blocks such as network interface controllers . This allows Xeon D processors to function as SoCs that do not require a separate southbridge PCH. It was announced in 2014 and the first Xeon D processors were released in March 2015. Xeon D processors come in an soldered BGA package rather than in
9471-479: The Xeon Scalable brand, there exists the hierarchy of Xeon Bronze, Silver, Gold and Platinum. In April 2024, Intel announced at its Vision event that the Xeon Scalable brand would be retired, beginning with 6th generation Xeon processors codenamed Sierra Forest and Granite Rapids that will now be referred to as "Xeon 6" processors. This change brings greater emphasis on processor generation numbers. With
9594-434: The advanced but delayed 5k86 ( K5 ), which, internally, was closely based on AMD's earlier 29K RISC design; similar to NexGen 's Nx586 , it used a strategy such that dedicated pipeline stages decode x86 instructions into uniform and easily handled micro-operations , a method that has remained the basis for most x86 designs to this day. Some early versions of these microprocessors had heat dissipation problems. The 6x86
9717-415: The art, had been planned for 2021; as of March 2022 the release had not taken place, however. The instruction set architecture has twice been extended to a larger word size. In 1985, Intel released the 32-bit 80386 (later known as i386) which gradually replaced the earlier 16-bit chips in computers (although typically not in embedded systems ) during the following years; this extended programming model
9840-464: The blade-server and embedded markets), and was rated at a thermal design power (TDP) of 31 W (LV: 1.66 GHz, 2 GHz and 2.16 GHz) and 15 W (ULV: 1.66 GHz). As such, it supported most of the same features as earlier Xeons: Virtualization Technology, 667 MT/s front side bus, and dual-core processing, but did not support 64-bit operations, so it could not run 64-bit server software, such as Microsoft Exchange Server 2007, and therefore
9963-424: The corresponding YMM register. Clock rate The clock rate of the first generation of computers was measured in hertz or kilohertz (kHz), the first personal computers (PCs) to arrive throughout the 1970s and 1980s had clock rates measured in megahertz (MHz), and in the 21st century the speed of modern CPUs is commonly advertised in gigahertz (GHz). This metric is most useful when comparing processors within
10086-450: The crystal reference frequency). The clock distribution network inside the CPU carries that clock signal to all the parts that need it. An A/D Converter has a "clock" pin driven by a similar system to set the sampling rate . With any particular CPU, replacing the crystal with another crystal that oscillates at half the frequency (" underclocking ") will generally make the CPU run at half the performance and reduce waste heat produced by
10209-527: The dual-core CPU (Xeon branded 5200 series) codenamed Wolfdale-DP (product code 80573). It is built on a 45 nm process like the desktop Core 2 Duo and Xeon Wolfdale , featuring Intel 64 (Intel's x86-64 implementation), the XD bit , and Virtualization Technology . It is unclear whether the Demand-based switching power management is available on the L5238. Wolfdale has 6 MB of shared L2 cache. The 7200 series, codenamed Tigerton (product code 80564)
10332-516: The dual-core Xeon 7000-series, was produced using a 90 nm process. Paxville MP clock ranges between 2.67 GHz and 3.0 GHz (model numbers 7020–7041), with some models having a 667 MT/s FSB, and others having an 800 MT/s FSB. Released on August 29, 2006, the 7100 series, codenamed Tulsa (product code 80550), is an improved version of Paxville MP, built on a 65 nm process, with 2 MB of L2 cache (1 MB per core) and up to 16 MB of L3 cache. It uses Socket 604 . Tulsa
10455-515: The electronic and physical levels. Quite naturally, early compatible microprocessors were 16-bit, while 32-bit designs were developed much later. For the personal computer market, real quantities started to appear around 1990 with i386 and i486 compatible processors, often named similarly to Intel's original chips. After the fully pipelined i486 , in 1993 Intel introduced the Pentium brand name (which, unlike numbers, could be trademarked ) for their new set of superscalar x86 designs. With
10578-459: The end of September 2006, was the first Xeon for single-CPU operation and is designd for entry-level uniprocessor servers. The same processor is branded as Core 2 Duo or as Pentium Dual-Core and Celeron , with varying features disabled. They use LGA 775 (Socket T), operate on a 1066 MT/s front-side bus, support Enhanced Intel SpeedStep Technology and Intel Virtualization Technology but do not support hyper-threading. Conroe processors with
10701-414: The exception of Xeon W-3175X ). Despite such disadvantages, Xeon processors have always had popularity among some desktop users (video editors and other power users ), mainly due to higher core count potential, and higher performance to price ratio vs. the Core i7 in terms of total computing power of all cores. Since most Intel Xeon CPUs lack an integrated GPU , systems built with those processors require
10824-401: The execution units with the decode steps opens up possibilities for more analysis of the (buffered) code stream, and therefore permits detection of operations that can be performed in parallel, simultaneously feeding more than one execution unit. The latest processors also do the opposite when appropriate; they combine certain x86 sequences (such as a compare followed by a conditional jump) into
10947-549: The first two actively produce modern 64-bit designs, leading to what has been called a "duopoly" of Intel and AMD in x86 processors. However, in 2014 the Shanghai-based Chinese company Zhaoxin , a joint venture between a Chinese company and VIA Technologies, began designing VIA based x86 processors for desktops and laptops. The release of its newest "7" family of x86 processors (e.g. KX-7000), which are not quite as fast as AMD or Intel chips but are still state of
11070-528: The formula: Addressing modes for 32-bit x86 processor modes can be summarized by the formula: Addressing modes for the 64-bit processor mode can be summarized by the formula: Instruction relative addressing in 64-bit code (RIP + displacement, where RIP is the instruction pointer register ) simplifies the implementation of position-independent code (as used in shared libraries in some operating systems). The 8086 had 64 KB of eight-bit (or alternatively 32 K-word of 16-bit ) I/O space, and
11193-399: The frequently occurring cases or contexts where a −128..127 range is enough. Typical instructions are therefore 2 or 3 bytes in length (although some are much longer, and some are single-byte). To further conserve encoding space, most registers are expressed in opcodes using three or four bits, the latter via an opcode prefix in 64-bit mode, while at most one operand to an instruction can be
11316-435: The high end, x86 continues to dominate computation-intensive workstation and cloud computing segments. In the 1980s and early 1990s, when the 8088 and 80286 were still in common use, the term x86 usually represented any 8086-compatible CPU. Today, however, x86 usually implies binary compatibility with the 32-bit instruction set of the 80386 . This is due to the fact that this instruction set has become something of
11439-501: The implementation of position-independent code , used in shared libraries in some operating systems. SIMD registers XMM0–XMM15 (XMM0–XMM31 when AVX-512 is supported). SIMD registers YMM0–YMM15 (YMM0–YMM31 when AVX-512 is supported). Lower half of each of the YMM registers maps onto the corresponding XMM register. SIMD registers ZMM0–ZMM31. Lower half of each of the ZMM registers maps onto
11562-408: The instruction pointer (IP) points to the next instruction that will be fetched from memory and then executed; this register cannot be directly accessed (read or written) by a program. The Intel 80186 and 80188 are essentially an upgraded 8086 or 8088 CPU, respectively, with on-chip peripherals added, and they have the same CPU registers as the 8086 and 8088 (in addition to interface registers for
11685-518: The launch of Intel's Sierra Forest line of processors, branding for mainstream server processors switched to Xeon #, with the # being the generation of the processor, such as Xeon 6 for the 6th generation of Xeon processors, this naming convention also carries over to the Granite Rapids line of server CPUs. Xeon 6 is split into two product lines, the E series and P series, which, respectively, are all E core and all P core designs. For example,
11808-447: The lower 16 bits of the new 32-bit EAX register, SI corresponds to the lower 16 bits of ESI, and so on. The general-purpose registers, base registers, and index registers can all be used as the base in addressing modes, and all of those registers except for the stack pointer can be used as the index in addressing modes. Two new segment registers (FS and GS) were added. With a greater number of registers, instructions and operands,
11931-434: The lower clock rate, e.g., 3.3 GHz, and sold at a lower price. The clock rate of a CPU is normally determined by the frequency of an oscillator crystal . Typically a crystal oscillator produces a fixed sine wave —the frequency reference signal. Electronic circuitry translates that into a square wave at the same frequency for digital electronics applications (or, when using a CPU multiplier , some fixed multiple of
12054-457: The model. These processors fit in the LGA 771 package. All models feature Intel 64 (Intel's x86-64 implementation), the XD bit , and Virtualization Technology . All except the E5405 and L5408 also feature Demand-based switching . The supplementary character in front of the model-number represents the thermal rating: an L depicts a TDP of 40 W or 50 W, an E depicts 80 W whereas an X
12177-428: The most complicated instructions with the data patterns that take the longest to settle (testing at the temperature and voltage that gives the lowest performance). Processors successfully tested for compliance with a given set of standards may be labeled with a higher clock rate, e.g., 3.50 GHz, while those that fail the standards of the higher clock rate yet pass the standards of a lower clock rate may be labeled with
12300-473: The name EM64T and finally using Intel 64. Microsoft and Sun Microsystems / Oracle also use term "x64", while many Linux distributions , and the BSDs also use the "amd64" term. Microsoft Windows, for example, designates its 32-bit versions as "x86" and 64-bit versions as "x64", while installation files of 64-bit Windows versions are required to be placed into a directory called "AMD64". In 2023, Intel proposed
12423-416: The next clock pulse comes before that, the results will be incorrect. In the process of transitioning, some energy is wasted as heat (mostly inside the driving transistors). When executing complicated instructions that cause many transitions, the higher the clock rate the more heat produced. Transistors may be damaged by excessive heat. There is also a lower limit of the clock rate, unless a fully static core
12546-454: The peripherals). The 8086, 8088, 80186, and 80188 can use an optional floating-point coprocessor, the 8087 . The 8087 appears to the programmer as part of the CPU and adds eight 80-bit wide registers, st(0) to st(7), each of which can hold numeric data in one of seven formats: 32-, 64-, or 80-bit floating point, 16-, 32-, or 64-bit (binary) integer, and 80-bit packed decimal integer. It also has its own 16-bit status register accessible through
12669-519: The same family, holding constant other features that may affect performance . Manufacturers of modern processors typically charge higher prices for processors that operate at higher clock rates, a practice called binning . For a given CPU, the clock rates are determined at the end of the manufacturing process through testing of each processor. Chip manufacturers publish a "maximum clock rate" specification, and they test chips before selling them to make sure they meet that specification, even when executing
12792-418: The same order as given in the instruction stream. Some Intel CPUs ( Xeon Foster MP , some Pentium 4 , and some Nehalem and later Intel Core processors) and AMD CPUs (starting from Zen ) are also capable of simultaneous multithreading with two threads per core ( Xeon Phi has four threads per core). Some Intel CPUs support transactional memory ( TSX ). When introduced, in the mid-1990s, this method
12915-443: The same simplified segmentation as long mode. The x86 architecture is a variable instruction length, primarily " CISC " design with emphasis on backward compatibility . The instruction set is not typical CISC, however, but basically an extended version of the simple eight-bit 8008 and 8080 architectures. Byte-addressing is enabled and words are stored in memory with little-endian byte order. Memory access to unaligned addresses
13038-508: The slightly slower AMD FX-8370 overclocked to 8.72 GHz which tops off the HWBOT frequency rankings. These records were broken in late 2022 when an Intel Core i9-13900K was overclocked to 9.008 GHz. The highest base clock rate on a production processor is the i9-14900KS , clocked at 6.2 GHz, which was released in Q1 2024. Engineers continue to find new ways to design CPUs that settle
13161-454: The stack. Much work has therefore been invested in making such accesses as fast as register accesses—i.e., a one cycle instruction throughput, in most circumstances where the accessed data is available in the top-level cache. A dedicated floating-point processor with 80-bit internal registers, the 8087 , was developed for the original 8086 . This microprocessor subsequently developed into the extended 80387 , and later processors incorporated
13284-490: The x86 naming scheme now legally cleared, other x86 vendors had to choose different names for their x86-compatible products, and initially some chose to continue with variations of the numbering scheme: IBM partnered with Cyrix to produce the 5x86 and then the very efficient 6x86 (M1) and 6x86 MX ( MII ) lines of Cyrix designs, which were the first x86 microprocessors implementing register renaming to enable speculative execution . AMD meanwhile designed and manufactured
13407-432: The x86-compatible VIA C7 , VIA Nano , AMD 's Geode , Athlon Neo and Intel Atom are examples of 32- and 64-bit designs used in some relatively low-power and low-cost segments. There have been several attempts, including by Intel, to end the market dominance of the "inelegant" x86 architecture designed directly from the first simple 8-bit microprocessors. Examples of this are the iAPX 432 (a project originally named
13530-484: The years, almost consistently with full backward compatibility . The architecture family has been implemented in processors from Intel, Cyrix , AMD , VIA Technologies and many other companies; there are also open implementations, such as the Zet SoC platform (currently inactive). Nevertheless, of those, only Intel, AMD, VIA Technologies, and DM&P Electronics hold x86 architectural licenses, and from these, only
13653-421: Was a " Deschutes " Pentium II (and shared the same product code: 80523) with a full-speed 512 kB (1 kB = 1024 B), 1 MB (1 MB = 1024 kB = 1024 B), or 2 MB L2 cache . The L2 cache was implemented with custom 512 kB SRAMs developed by Intel. The number of SRAMs depended on the amount of cache. A 512 kB configuration required one SRAM, a 1 MB configuration: two SRAMs, and
13776-494: Was almost always outperformed by the older Cascades cores with a 2 MB L2 cache and AMD's Athlon MP . Combined with the need to use expensive Rambus Dynamic RAM , the Foster's sales were somewhat unimpressive. At most two Foster processors could be accommodated in a symmetric multiprocessing (SMP) system built with a mainstream chipset, so a second version ( Foster MP ) was introduced with 512 KB or 1 MB L3 cache and
13899-537: Was also affected by a few minor compatibility problems, the Nx586 lacked a floating-point unit (FPU) and (the then crucial) pin-compatibility, while the K5 had somewhat disappointing performance when it was (eventually) introduced. Customer ignorance of alternatives to the Pentium series further contributed to these designs being comparatively unsuccessful, despite the fact that the K5 had very good Pentium compatibility and
14022-424: Was an MP version of Nocona , while the more expensive " Potomac " was a Cranford with 8 MB of L3 cache. Like Nocona and Irwindale, they also have product code 80546. The first dual-core CPU branded Xeon, codenamed Paxville DP , product code 80551, was released by Intel on October 10, 2005. Paxville DP had NetBurst microarchitecture , and was a dual-core equivalent of the single-core Irwindale (related to
14145-618: Was based on the Pentium III " Coppermine " core. The " Cascades " Xeon used a 133 MT/s front side bus and relatively small 256 kB on-die L2 cache resulting in almost the same capabilities as the Slot 1 Coppermine processors, which were capable of dual-processor operation but not quad-processor or octa-processor operation. To improve this situation, Intel released another version, officially also named " Cascades ", but often referred to as " Cascades 2 MB ". That came in two variants: with 1 MB or 2 MB of L2 cache. Its bus speed
14268-524: Was designed to emulate the Core i3, i5, i7 and i9 branding that Intel had been using for its desktop processors. Some shortcomings that make Xeon processors unsuitable for most consumer-grade desktop PCs include lower clock rates at the same price point (since servers run more tasks in parallel than desktops, core counts are more important than clock rates), and, usually, the lack of an integrated graphics processing unit (GPU). Processor models prior to Sapphire Rapids-WS lack support for overclocking (with
14391-457: Was fixed at 100 MT/s, though in practice the cache was able to offset this. The product code for Cascades mirrored that of Coppermine ; 80526. In mid-2001, the Xeon brand was introduced ("Pentium" was dropped from the name). The initial variant that used the new NetBurst microarchitecture , " Foster ", was slightly different from the desktop Pentium 4 (" Willamette "). It was a decent chip for workstations, but for server applications it
14514-547: Was limited to 16 GB of memory. A planned successor, codenamed " Merom MP " was to be a drop-in upgrade to enable Sossaman -based servers to upgrade to 64-bit capability. However, this was abandoned in favor of low-voltage versions of the Woodcrest LV processor leaving the Sossaman at a dead-end with no upgrade path. The 3000 series, codenamed Conroe (product code 80557) dual-core Xeon (branded) CPU, released at
14637-403: Was originally referred to as the i386 architecture (like its first implementation) but Intel later dubbed it IA-32 when introducing its (unrelated) IA-64 architecture. In 1999–2003, AMD extended this 32-bit architecture to 64 bits and referred to it as x86-64 in early documents and later as AMD64 . Intel soon adopted AMD's architectural extensions under the name IA-32e, later using
14760-497: Was quite temporary, lasting for a few years during the early 1980s. Although the 8086 was primarily developed for embedded systems and small multi-user or single-user computers, largely as a response to the successful 8080-compatible Zilog Z80 , the x86 line soon grew in features and processing power. Today, x86 is ubiquitous in both stationary and portable personal computers, and is also used in midrange computers , workstations , servers, and most new supercomputer clusters of
14883-517: Was released in early 2005, with 2 MB L2 cache and the ability to have its clock speed reduced during low processor demand. Although it was a bit more competitive than the Nocona had been, independent tests showed that AMD's Opteron still outperformed Irwindale . Both of these Prescott-derived Xeons have the product code 80546. 64-bit Xeon MPs were introduced in April 2005. The cheaper " Cranford "
15006-574: Was released in two lines: the N-line uses a 667 MT/s FSB, and the M-line uses an 800 MT/s FSB. The N-line ranges from 2.5 GHz to 3.5 GHz (model numbers 7110N-7150N), and the M-line ranges from 2.6 GHz to 3.4 GHz (model numbers 7110M-7140M). L3 cache ranges from 4 MB to 16 MB across the models. On May 23, 2006, Intel released the dual-core CPU (Xeon branded 5000 series) codenamed Dempsey (product code 80555). Released as
15129-436: Was sometimes referred to as a "RISC core" or as "RISC translation", partly for marketing reasons, but also because these micro-operations share some properties with certain types of RISC instructions. However, traditional microcode (used since the 1950s) also inherently shares many of the same properties; the new method differs mainly in that the translation to micro-operations now occurs asynchronously. Not having to synchronize
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