AMD K5

Last updated
AMD K5
AMD K5 PR166 Front.jpg
An AMD K5 PR166 microprocessor
General information
LaunchedMarch 27, 1996 (SSA/5)
October 7, 1996 (5k86)
Common manufacturer(s)
Performance
Max. CPU clock rate 75 MHz to 133 MHz
FSB speeds50 MHz to 66 MHz
Cache
L1 cache 8 KB + 16 KB
(data + instructions)
Architecture and classification
ApplicationDesktop, Embedded
Microarchitecture K5
Instruction set IA-32/x86
Physical specifications
Transistors
  • 4.3M 500 nm
Cores
  • 1
Socket(s)
Products, models, variants
Model(s)
  • SSA/5 Series
  • 5k86 Series
History
Predecessor(s) Am5x86
Successor(s) K6

The K5 is AMD's first x86 processor to be developed entirely in-house. Introduced in March 1996, its primary competition was Intel's Pentium microprocessor. The K5 was an ambitious design, closer to a Pentium Pro than a Pentium regarding technical solutions and internal architecture. However, the final product was closer to the Pentium regarding performance, although faster clock-for-clock compared to the Pentium.

Contents

Technical details

K5 core diagram AMDK5Diagram.png
K5 core diagram

The K5 was based upon an internal highly parallel RISC processor architecture with an x86 decoding front-end. [1] The K5 offered good x86 compatibility and the in-house-developed test suite proved invaluable on later projects. All models had 4.3 million transistors, with five integer units that could process instructions out of order and one floating-point unit. The branch target buffer was four times the size of the Pentium's and register renaming helped overcome register dependencies. [2] The chip's speculative execution of instructions reduced pipeline stalls. It had a 16 KB four-way set-associative instruction cache and an 8 KB data cache. The floating-point divide and square-root microcode were mechanically proven. [3] [4] The floating-point transcendental instructions were implemented in hardware and were faithful to true mathematical results for all operands. [5]

Performance

The K5 project represented an early chance for AMD to take technical leadership from Intel. Although the chip addressed the right design concepts, the actual engineering implementation had its issues. The low clock rates were, in part, due to AMD's limitations as a "cutting edge" manufacturing company at the time, and in part due to the design itself, which had many levels of logic for the process technology of the day, hampering clock scaling. Additionally, while the K5's floating-point performance was regarded as superior to that of the Cyrix 6x86,[ clarification needed ] it was slower than that of the Pentium, although offering more reliable transcendental function results. Because it was late to market and did not meet performance expectations, the K5 never gained the acceptance among large computer manufacturers that the earlier Am486 and later AMD K6 enjoyed.

Features

Models

There were two revisions of the K5 architecture, internally called the SSA/5 and the 5k86, both released with the K5 label. The original set of "SSA/5" CPUs had its branch prediction unit disabled and additional internal waitstates added; these issues were remedied with the "5k86", resulting in up to 30% better performance clock for clock. [6] [7] The "SSA/5" line ran from 75 to 100 MHz; the "5k86" line ran from 90 to 133 MHz. However, AMD used what it called a PR rating, or performance rating, to label the chips according to their suggested equivalence in integer performance to a Pentium of that clock speed. Thus, a 116 MHz chip from the second line was marketed as the "K5 PR166". Manufacturing delays caused the PR200's arrival to nearly align with the release of K6. Since AMD did not want the two chips competing, the K5-PR200 only arrived in small numbers.

SSA/5

AMD 5K86-P90 (SSA/5) AMD5k86-P90 SSA5-90ABQ.jpg
AMD 5K86-P90 (SSA/5)
AMD K5 PR75 (SSA/5) die shot AMD K5 PR75 die.JPG
AMD K5 PR75 (SSA/5) die shot

5k86

AMD K5 PR150 (5k86) die shot AMD K5 die2.JPG
AMD K5 PR150 (5k86) die shot

Related Research Articles

<span class="mw-page-title-main">Athlon</span> Brand name for several AMD processors

Athlon is the brand name applied to a series of x86-compatible microprocessors designed and manufactured by AMD. The original Athlon was the first seventh-generation x86 processor and the first desktop processor to reach speeds of one gigahertz (GHz). It made its debut as AMD's high-end processor brand on June 23, 1999. Over the years AMD has used the Athlon name with the 64-bit Athlon 64 architecture, the Athlon II, and Accelerated Processing Unit (APU) chips targeting the Socket AM1 desktop SoC architecture, and Socket AM4 Zen microarchitecture. The modern Zen-based Athlon with a Radeon Graphics processor was introduced in 2019 as AMD's highest-performance entry-level processor.

<span class="mw-page-title-main">Cyrix 6x86</span> Microprocessor

The Cyrix 6x86 is a line of sixth-generation, 32-bit x86 microprocessors designed and released by Cyrix in 1995. Cyrix, being a fabless company, had the chips manufactured by IBM and SGS-Thomson. The 6x86 was made as a direct competitor to Intel's Pentium microprocessor line, and was pin compatible. During the 6x86's development, the majority of applications performed almost entirely integer operations. The designers foresaw that future applications would most likely maintain this instruction focus. So, to optimize the chip's performance for what they believed to be the most likely application of the CPU, the integer execution resources received most of the transistor budget. This would later prove to be a strategic mistake, as the popularity of the P5 Pentium caused many software developers to hand-optimize code in assembly language, to take advantage of the P5 Pentium's tightly pipelined and lower latency FPU. For example, the highly anticipated first-person shooter Quake used highly optimized assembly code designed almost entirely around the P5 Pentium's FPU. As a result, the P5 Pentium significantly outperformed other CPUs in the game.

i486 Successor to the Intel 386

The Intel 486, officially named i486 and also known as 80486, is a microprocessor. It is a higher-performance follow-up to the Intel 386. The i486 was introduced in 1989. It represents the fourth generation of binary compatible CPUs following the 8086 of 1978, the Intel 80286 of 1982, and 1985's i386.

<span class="mw-page-title-main">AMD K6</span> Computer microprocessor

The K6 microprocessor was launched by AMD in 1997. The main advantage of this particular microprocessor is that it was designed to fit into existing desktop designs for Pentium-branded CPUs. It was marketed as a product that could perform as well as its Intel Pentium II equivalent but at a significantly lower price. The K6 had a considerable impact on the PC market and presented Intel with serious competition.

<span class="mw-page-title-main">Pentium (original)</span> Intel microprocessor

The Pentium is a x86 microprocessor introduced by Intel on March 22, 1993. It is the first CPU using the Pentium brand. Considered the fifth generation in the 8086 compatible line of processors, its implementation and microarchitecture was internally called P5.

<span class="mw-page-title-main">Duron</span> Series of CPUs by AMD

Duron is a line of budget x86-compatible microprocessors manufactured by AMD and released on June 19, 2000. Duron was intended to be a lower-cost offering to complement AMD's then mainstream performance Athlon processor line, and it also competed with rival chipmaker Intel's Pentium III and Celeron processor offerings. The Duron brand name was retired in 2004, succeeded by the AMD's Sempron line of processors as their budget offering.

<span class="mw-page-title-main">Cyrix</span> American microprocessor developer

Cyrix Corporation was a microprocessor developer that was founded in 1988 in Richardson, Texas, as a specialist supplier of floating point units for 286 and 386 microprocessors. The company was founded by Tom Brightman and Jerry Rogers.

<span class="mw-page-title-main">Pentium II</span> Intel microprocessor

The Pentium II brand refers to Intel's sixth-generation microarchitecture ("P6") and x86-compatible microprocessors introduced on May 7, 1997. Containing 7.5 million transistors, the Pentium II featured an improved version of the first P6-generation core of the Pentium Pro, which contained 5.5 million transistors. However, its L2 cache subsystem was a downgrade when compared to the Pentium Pros. It is a single-core microprocessor.

<span class="mw-page-title-main">Pentium III</span> Line of desktop and mobile microprocessors produced by Intel

The Pentium III brand refers to Intel's 32-bit x86 desktop and mobile CPUs based on the sixth-generation P6 microarchitecture introduced on February 28, 1999. The brand's initial processors were very similar to the earlier Pentium II-branded processors. The most notable differences were the addition of the Streaming SIMD Extensions (SSE) instruction set, and the introduction of a controversial serial number embedded in the chip during manufacturing. The Pentium III is also a single-core processor.

<span class="mw-page-title-main">Pentium Pro</span> Sixth-generation x86 microprocessor by Intel

The Pentium Pro is a sixth-generation x86 microprocessor developed and manufactured by Intel and introduced on November 1, 1995. It introduced the P6 microarchitecture and was originally intended to replace the original Pentium in a full range of applications. While the Pentium and Pentium MMX had 3.1 and 4.5 million transistors, respectively, the Pentium Pro contained 5.5 million transistors. Later, it was reduced to a more narrow role as a server and high-end desktop processor and was used in supercomputers like ASCI Red, the first computer to reach the trillion floating point operations per second (teraFLOPS) performance mark in 1996. The Pentium Pro was capable of both dual- and quad-processor configurations. It only came in one form factor, the relatively large rectangular Socket 8. The Pentium Pro was succeeded by the Pentium II Xeon in 1998.

<span class="mw-page-title-main">Cyrix 5x86</span> 1995 line of x86-compatible microprocessors

The Cyrix 5x86 was a line of x86 microprocessors designed by Cyrix and released on June 5 of 1995. Cyrix, being a fabless company, had the chips manufactured by IBM. The line came out about 5 months before the more famous Cyrix 6x86. The Cyrix 5x86 was one of the fastest CPUs ever produced for Socket 3 computer systems. With better performance in most applications than an Intel Pentium processor at 75 MHz, the Cyrix Cx5x86 filled a gap by providing a medium-performance processor option for 486 Socket 3 motherboards.

<span class="mw-page-title-main">Am5x86</span> 486 computer chip made by AMD

The Am5x86 processor is an x86-compatible CPU announced in November of 1995 by AMD for use in 486-class computer systems. It began shipping in December of 1995, with a base price of $93 per unit in bulk quantities. Before being released, it was in development under the codename "X5".

<span class="mw-page-title-main">AMD K6-2</span> CPU by AMD

The K6-2 is an x86 microprocessor introduced by AMD on May 28, 1998, and available in speeds ranging from 266 to 550 MHz. An enhancement of the original K6, the K6-2 introduced AMD's 3DNow! SIMD instruction set and an upgraded system-bus interface called Super Socket 7, which was backward compatible with older Socket 7 motherboards. It was manufactured using a 250 nanometer process, ran at 2.2 volts, and had 9.3 million transistors.

<span class="mw-page-title-main">AMD K6-III</span> Microprocessor series by AMD

The K6-III was an x86 microprocessor line manufactured by AMD that launched on February 22, 1999. The launch consisted of both 400 and 450 MHz models and was based on the preceding K6-2 architecture. Its improved 256 KB on-chip L2 cache gave it significant improvements in system performance over its predecessor the K6-2. The K6-III was the last processor officially released for desktop Socket 7 systems, however later mobile K6-III+ and K6-2+ processors could be run unofficially in certain socket 7 motherboards if an updated BIOS was made available for a given board. The Pentium III processor from Intel launched 6 days later.

NexGen, Inc. was a private semiconductor company based in Milpitas, California, that designed x86 microprocessors until it was purchased by AMD in 1996. NexGen was a fabless design house that designed its chips but relied on other companies for production. NexGen's chips were produced by IBM's Microelectronics division in Burlington, Vermont alongside PowerPC and DRAM parts.

<span class="mw-page-title-main">WinChip</span> Series of CPUs

The WinChip series was a low-power Socket 7-based x86 processor designed by Centaur Technology and marketed by its parent company IDT.

<span class="mw-page-title-main">Sempron</span> Marketing name by AMD

Sempron has been the marketing name used by AMD for several different budget desktop CPUs, using several different technologies and CPU socket formats. The Sempron replaced the AMD Duron processor and competed against Intel's Celeron series of processors. AMD coined the name from the Latin semper, which means "always", to suggest the Sempron is suitable for "daily use, practical, and part of everyday life". The last Semprons were launched in April 2014. The brand was retired with the launch of the AMD A-Series APUs.

<span class="mw-page-title-main">AMD Am29000</span> Family of RISC microprocessors and microcontrollers

The AMD Am29000, commonly shortened to 29k, is a family of 32-bit RISC microprocessors and microcontrollers developed and fabricated by Advanced Micro Devices (AMD). Based on the seminal Berkeley RISC, the 29k added a number of significant improvements. They were, for a time, the most popular RISC chips on the market, widely used in laser printers from a variety of manufacturers.

<span class="mw-page-title-main">Athlon 64 X2</span> Series of CPUs by AMD

The Athlon 64 X2 is the first native dual-core desktop central processing unit (CPU) designed by Advanced Micro Devices (AMD). It was designed from scratch as native dual-core by using an already multi-CPU enabled Athlon 64, joining it with another functional core on one die, and connecting both via a shared dual-channel memory controller/north bridge and additional control logic. The initial versions are based on the E stepping model of the Athlon 64 and, depending on the model, have either 512 or 1024 KB of L2 cache per core. The Athlon 64 X2 can decode instructions for Streaming SIMD Extensions 3 (SSE3), except those few specific to Intel's architecture. The first Athlon 64 X2 CPUs were released in May 2005, in the same month as Intel's first dual-core processor, the Pentium D.

References

  1. AMD-K5 Processor Technical Reference Manual (PDF). AMD. November 1996.
  2. "AMD-K5 Processor Data Sheet" (PDF). AMD. January 1997.
  3. Moore, J. Strother; Lynch, Thomas W.; Kaufmann, Matt (September 1998). "A Mechanically Checked Proof of the AMD5K86TM Floating-Point Division Program". IEEE Transactions on Computers . Washington, DC, USA: IEEE Computer Society. 47 (9): 913–926. doi:10.1109/12.713311.
  4. Russinoff, David M. (January 1999). "A Mechanically Checked Proof of Correctness of the AMD K5 Floating Point Square Root Microcode". Formal Methods in System Design. Hingham, MA, USA: Kluwer Academic Publishers. 14 (1): 75–125. doi:10.1023/A:1008669628911. S2CID   22941018.
  5. Lynch, T.; Ahmed, A.; Schulte, M.; Callaway, T.; Tisdale, R. (19–21 July 1995). "The K5 Transcendental Functions". Proceedings of the 12th Symposium on Computer Arithmetic. Washington, DC, USA: IEEE Computer Society. pp. 163–170. doi:10.1109/ARITH.1995.465368. ISBN   0-8186-7089-4.
  6. "X86 CPU Reference (Part 2)". alasir.com. Archived from the original on 26 July 2017. Retrieved 12 January 2022.
  7. "Microprocessor History - AMD K5". May 2019.

Further reading