AMD K6-III
Encyclopedia
The K6-III, code-named "Sharptooth", was an x86 microprocessor
manufactured by AMD, released on 22 February 1999, with 400 and 450 MHz models. It was the last Socket 7
desktop processor. For an extremely short time after its release, the fastest available desktop processor from Intel was the Pentium II 450 MHz. However, the K6-III also competed against the Pentium III "Katmai" line, released just days later on February 26. "Katmai" CPUs reached speeds of 500 MHz, slightly faster than the K6-III 450 MHz. K6-III performance was significantly improved over the K6-2 due to the addition of an on-die L2 cache running at full clock speed. When equipped with a 1MB L3 cache (on the motherboard) the 400 and 450 MHz K6-IIIs is claimed by Ars Technica to often outperform the hugely higher-priced Pentium III "Katmai" 450- and 500-MHz models, respectively.
In conception, the design is simple: it was a K6-2 with on-die L2 cache
. In execution, however, the design was not simple; with 21.4 million transistors. The pipeline was short compared to that of the Pentium III and thus the design did not scale well past 500 MHz. Nevertheless, the K6-III 400 sold well, and the AMD K6-III 450 was clearly the fastest x86 chip on the market on introduction, comfortably outperforming AMD K6-2s and Intel Pentium IIs.
) operations by a packed single-precision floating-point data format. It was an enhancement to the MMX instruction set, which contained 21 new instructions that support SIMD floating-point operations and includes SIMD integer operations, data prefetch, and faster MMX-to-floating-point switching. The K6-III+ had the "Enhanced 3DNow!"(Extended 3DNow! or 3DNow+) which added 5 new DSP instructions, but not the 19 new extended MMX instructions.
and re-badged it as the "Pentium III
". The base design was unchanged (the addition of SSE
instructions was at that time of no performance significance) but Intel's new production process allowed clockspeed improvements, and it became difficult to determine which company's part was the faster. Most industry observers regarded the Intel part as superior for floating-point intensive tasks (such as most 3D games), but the K6-III as better for mainstream integer work.
Both firms were keen to establish a clear lead, and both experienced manufacturing problems with their higher-frequency parts. AMD chose not to sell a 500 MHz or faster K6-III after the rare 500 MHz K6-III had been immediately recalled; it was found to be drawing enough current to damage some motherboards. AMD preferred to concentrate on their soon-to-be-released Athlon
instead. Intel produced a 550 MHz Pentium III with some success but their 600 MHz version had reliability issues and was soon recalled.
With the release of the Athlon
, the K6-III became something of an orphan. No longer a competitive CPU in its intended market segment, it nevertheless required substantial manufacturing resources to produce: at 21.4 million transistors, it was almost as expensive to make a K6-III as a 22-million-transistor Athlon, and the same area of silicon could make more than two of the 9.3 million-transistor K6-2 CPUs. For a time, the K6-III was a low priority part for AMD—something to be made only when all orders for high-priced Athlons and cheap-to-produce K6-2s had been filled—and it became difficult to obtain in significant quantities.
The original K6-III went out of production when Intel released their "Coppermine" Pentium III (a much improved part that used an on-die cache) and, at the same time, switched to a new production process. The changeover was fraught with difficulties and Intel CPUs were in global short supply for 12 months or more. This, coupled with the better performance of the Athlon, resulted in even many former Intel-only manufacturers ordering Athlon parts, and stretched AMD's manufacturing facilities to the limit. In consequence, AMD stopped making the K6-III in order to leave more room to manufacture Athlons (and K6-2s).
power saving technology. Essentially, the power savings were achieved with a combination of frequency (through adjusting multipliers) and voltage reduction.
Although targeted at notebook computers, both parts were also used by enthusiasts in desktop systems. AMD continued to devote their marketing resources to the Athlon and neither part became well-known outside the industry, but both had modest success and became firm favourites with the overclocking community. K6-III+ 450 MHz CPUs routinely overclocked to almost 600 MHz. Unfortunately, even with the 180 nm process, the K6 architecture's short 6-stage pipeline was stretched to the limit with regards to clock speed ramping. While the new "Coppermine" Pentium III was able to rise up to a final 1.13 GHz clock speed, K6 III+ and 2+ never clocked higher than 570 MHz officially, with overclockers
using air cooling achieving around 800 MHz at best.
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
manufactured by AMD, released on 22 February 1999, with 400 and 450 MHz models. It was the last Socket 7
Socket 7
Socket 7 is a physical and electrical specification for an x86-style CPU socket on a personal computer motherboard. The socket supersedes the earlier Socket 5, and accepts P5 Pentium microprocessors manufactured by Intel, as well as compatibles made by Cyrix/IBM, AMD, IDT and others.Socket 7 was...
desktop processor. For an extremely short time after its release, the fastest available desktop processor from Intel was the Pentium II 450 MHz. However, the K6-III also competed against the Pentium III "Katmai" line, released just days later on February 26. "Katmai" CPUs reached speeds of 500 MHz, slightly faster than the K6-III 450 MHz. K6-III performance was significantly improved over the K6-2 due to the addition of an on-die L2 cache running at full clock speed. When equipped with a 1MB L3 cache (on the motherboard) the 400 and 450 MHz K6-IIIs is claimed by Ars Technica to often outperform the hugely higher-priced Pentium III "Katmai" 450- and 500-MHz models, respectively.
Architecture
CPU cache
A CPU cache is a cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations...
. In execution, however, the design was not simple; with 21.4 million transistors. The pipeline was short compared to that of the Pentium III and thus the design did not scale well past 500 MHz. Nevertheless, the K6-III 400 sold well, and the AMD K6-III 450 was clearly the fastest x86 chip on the market on introduction, comfortably outperforming AMD K6-2s and Intel Pentium IIs.
3DNow!
A single instruction multiple data (SIMDSIMD
Single instruction, multiple data , is a class of parallel computers in Flynn's taxonomy. It describes computers with multiple processing elements that perform the same operation on multiple data simultaneously...
) operations by a packed single-precision floating-point data format. It was an enhancement to the MMX instruction set, which contained 21 new instructions that support SIMD floating-point operations and includes SIMD integer operations, data prefetch, and faster MMX-to-floating-point switching. The K6-III+ had the "Enhanced 3DNow!"(Extended 3DNow! or 3DNow+) which added 5 new DSP instructions, but not the 19 new extended MMX instructions.
TriLevel Cache
The original K6-2 had a 64 KB primary cache and a much larger amount of motherboard-mounted cache (usually 512 KB or 1024 KB but varying depending on the choice of motherboard). The K6-III, with its 256 KB on-die secondary cache, re-purposed the variable-size external cache on the motherboard as the L3 cache. This scheme was termed "TriLevel Cache" by AMD. The L3 cache has a capacity of up to 2 MB.Market performance
Intel's Pentium II replacement was not yet available but, as a stop-gap, Intel introduced a modestly revised version of the Pentium IIPentium II
The Pentium II brand refers to Intel's sixth-generation microarchitecture 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...
and re-badged it as the "Pentium III
Pentium III
The Pentium III brand refers to Intel's 32-bit x86 desktop and mobile microprocessors based on the sixth-generation P6 microarchitecture introduced on February 26, 1999. The brand's initial processors were very similar to the earlier Pentium II-branded microprocessors...
". The base design was unchanged (the addition of SSE
Streaming SIMD Extensions
In computing, Streaming SIMD Extensions is a SIMD instruction set extension to the x86 architecture, designed by Intel and introduced in 1999 in their Pentium III series processors as a reply to AMD's 3DNow! . SSE contains 70 new instructions, most of which work on single precision floating point...
instructions was at that time of no performance significance) but Intel's new production process allowed clockspeed improvements, and it became difficult to determine which company's part was the faster. Most industry observers regarded the Intel part as superior for floating-point intensive tasks (such as most 3D games), but the K6-III as better for mainstream integer work.
Both firms were keen to establish a clear lead, and both experienced manufacturing problems with their higher-frequency parts. AMD chose not to sell a 500 MHz or faster K6-III after the rare 500 MHz K6-III had been immediately recalled; it was found to be drawing enough current to damage some motherboards. AMD preferred to concentrate on their soon-to-be-released Athlon
Athlon
Athlon is the brand name applied to a series of x86-compatible microprocessors designed and manufactured by Advanced Micro Devices . The original Athlon was the first seventh-generation x86 processor and, in a first, retained the initial performance lead it had over Intel's competing processors...
instead. Intel produced a 550 MHz Pentium III with some success but their 600 MHz version had reliability issues and was soon recalled.
With the release of the Athlon
Athlon
Athlon is the brand name applied to a series of x86-compatible microprocessors designed and manufactured by Advanced Micro Devices . The original Athlon was the first seventh-generation x86 processor and, in a first, retained the initial performance lead it had over Intel's competing processors...
, the K6-III became something of an orphan. No longer a competitive CPU in its intended market segment, it nevertheless required substantial manufacturing resources to produce: at 21.4 million transistors, it was almost as expensive to make a K6-III as a 22-million-transistor Athlon, and the same area of silicon could make more than two of the 9.3 million-transistor K6-2 CPUs. For a time, the K6-III was a low priority part for AMD—something to be made only when all orders for high-priced Athlons and cheap-to-produce K6-2s had been filled—and it became difficult to obtain in significant quantities.
The original K6-III went out of production when Intel released their "Coppermine" Pentium III (a much improved part that used an on-die cache) and, at the same time, switched to a new production process. The changeover was fraught with difficulties and Intel CPUs were in global short supply for 12 months or more. This, coupled with the better performance of the Athlon, resulted in even many former Intel-only manufacturers ordering Athlon parts, and stretched AMD's manufacturing facilities to the limit. In consequence, AMD stopped making the K6-III in order to leave more room to manufacture Athlons (and K6-2s).
K6-III+ and K6-2+
By the time the x86 CPU shortage was over, AMD had developed revised versions of the K6 family: the K6-2+ and the K6-III+. Essentially, both parts were K6-IIIs (the 2+ with a 128 KiB cache, the III+ with the full 256 KiB) made on a new 180 nm production process. The K6-2+ and K6-III+ were specifically designed as low-power mobile CPUs, therefore they were the first processors to be available with the PowerNow!PowerNow!
PowerNow! is speed throttling and power saving technology of AMD's processors used in laptops. The CPU's clock speed and VCore are automatically decreased when the computer is under low load or idle, to save battery power, reduce heat and noise...
power saving technology. Essentially, the power savings were achieved with a combination of frequency (through adjusting multipliers) and voltage reduction.
Although targeted at notebook computers, both parts were also used by enthusiasts in desktop systems. AMD continued to devote their marketing resources to the Athlon and neither part became well-known outside the industry, but both had modest success and became firm favourites with the overclocking community. K6-III+ 450 MHz CPUs routinely overclocked to almost 600 MHz. Unfortunately, even with the 180 nm process, the K6 architecture's short 6-stage pipeline was stretched to the limit with regards to clock speed ramping. While the new "Coppermine" Pentium III was able to rise up to a final 1.13 GHz clock speed, K6 III+ and 2+ never clocked higher than 570 MHz officially, with overclockers
Overclocking
Overclocking is the process of operating a computer component at a higher clock rate than it was designed for or was specified by the manufacturer, but some manufacturers purposely underclock their components to improve battery life. Many people just overclock or 'rightclock' their hardware to...
using air cooling achieving around 800 MHz at best.
K6-III ("Sharptooth", K6-3D+, 250 nm)
- CPU ID: AuthenticAMD Family 5 Model 9
- L1-Cache: 32 + 32 KiB (Data + Instructions)
- L2-Cache: 256 KiB, fullspeed
- MMX, 3DNow!3DNow!3DNow! is an extension to the x86 instruction set developed by Advanced Micro Devices . It adds single instruction multiple data instructions to the base x86 instruction set, enabling it to perform simple vector processing, which improves the performance of many graphic-intensive applications...
- Socket 7Socket 7Socket 7 is a physical and electrical specification for an x86-style CPU socket on a personal computer motherboard. The socket supersedes the earlier Socket 5, and accepts P5 Pentium microprocessors manufactured by Intel, as well as compatibles made by Cyrix/IBM, AMD, IDT and others.Socket 7 was...
, Super7Super Socket 7The Super Socket 7, also referred to as Super 7, is an extension of the Socket 7 ZIF socket specification. It features a 100 MHz front-side bus, support for AGP, and a SPGA package. Super Socket was used by AMD K6-2 and K6-III processors, and some of the final Cyrix M-II processors... - Front side busFront side busA front-side bus is a computer communication interface often used in computers during the 1990s and 2000s.It typically carries data between the central processing unit and a memory controller hub, known as the northbridge....
: 66/100, 100 MHz - VCore: 2.2 V, 2.4 V
- First release: February 22, 1999
- Manufacturing process: 0.25 µm
- Clockrate: 400, 450 MHz
K6-III-P (250 nm, mobile)
- CPU ID: AuthenticAMD Family 5 Model 9
- L1-Cache: 32 + 32 KiB (Data + Instructions)
- L2-Cache: 256 KiB, fullspeed
- MMX, 3DNow!3DNow!3DNow! is an extension to the x86 instruction set developed by Advanced Micro Devices . It adds single instruction multiple data instructions to the base x86 instruction set, enabling it to perform simple vector processing, which improves the performance of many graphic-intensive applications...
- Socket 7Socket 7Socket 7 is a physical and electrical specification for an x86-style CPU socket on a personal computer motherboard. The socket supersedes the earlier Socket 5, and accepts P5 Pentium microprocessors manufactured by Intel, as well as compatibles made by Cyrix/IBM, AMD, IDT and others.Socket 7 was...
, Super7Super Socket 7The Super Socket 7, also referred to as Super 7, is an extension of the Socket 7 ZIF socket specification. It features a 100 MHz front-side bus, support for AGP, and a SPGA package. Super Socket was used by AMD K6-2 and K6-III processors, and some of the final Cyrix M-II processors... - Front side busFront side busA front-side bus is a computer communication interface often used in computers during the 1990s and 2000s.It typically carries data between the central processing unit and a memory controller hub, known as the northbridge....
: 66, 95, 96.2, 66/100, 100 MHz - VCore: 2.0 V, 2.2 V
- First release: May 31, 1999
- Manufacturing process: 0.25 µm
- Clockrate: 350, 366, 380, 400, 433, 450 MHz
K6-2+ (180 nm, mobile)
- CPU ID: AuthenticAMD Family 5 Model 13
- L1-Cache: 32 + 32 KiB (Data + Instructions)
- L2-Cache: 128 KiB, fullspeed
- MMX, Extended 3DNow!3DNow!3DNow! is an extension to the x86 instruction set developed by Advanced Micro Devices . It adds single instruction multiple data instructions to the base x86 instruction set, enabling it to perform simple vector processing, which improves the performance of many graphic-intensive applications...
, PowerNow!PowerNow!PowerNow! is speed throttling and power saving technology of AMD's processors used in laptops. The CPU's clock speed and VCore are automatically decreased when the computer is under low load or idle, to save battery power, reduce heat and noise... - Super Socket 7Super Socket 7The Super Socket 7, also referred to as Super 7, is an extension of the Socket 7 ZIF socket specification. It features a 100 MHz front-side bus, support for AGP, and a SPGA package. Super Socket was used by AMD K6-2 and K6-III processors, and some of the final Cyrix M-II processors...
- Front side busFront side busA front-side bus is a computer communication interface often used in computers during the 1990s and 2000s.It typically carries data between the central processing unit and a memory controller hub, known as the northbridge....
: 95, 97, 100 MHz - VCore: 2.0 V
- First release: April 18, 2000
- Manufacturing process: 0.18 µm
- Clockrate: 450, 475, 500, 533, 550 MHz. (570 MHz, undocumented)
K6-III+ (180 nm, mobile)
- CPU ID: AuthenticAMD Family 5 Model 13
- L1-Cache: 32 + 32 KiB (Data + Instructions)
- L2-Cache: 256 KiB, fullspeed
- MMX, Extended 3DNow!3DNow!3DNow! is an extension to the x86 instruction set developed by Advanced Micro Devices . It adds single instruction multiple data instructions to the base x86 instruction set, enabling it to perform simple vector processing, which improves the performance of many graphic-intensive applications...
, PowerNow!PowerNow!PowerNow! is speed throttling and power saving technology of AMD's processors used in laptops. The CPU's clock speed and VCore are automatically decreased when the computer is under low load or idle, to save battery power, reduce heat and noise... - Super7Super Socket 7The Super Socket 7, also referred to as Super 7, is an extension of the Socket 7 ZIF socket specification. It features a 100 MHz front-side bus, support for AGP, and a SPGA package. Super Socket was used by AMD K6-2 and K6-III processors, and some of the final Cyrix M-II processors...
- Front side busFront side busA front-side bus is a computer communication interface often used in computers during the 1990s and 2000s.It typically carries data between the central processing unit and a memory controller hub, known as the northbridge....
: 95, 100 MHz - VCore: 2.0 V, (1.6 V, 1.8 V low voltage types)
- First release: April 18, 2000
- Manufacturing process: 0.18 µm
- Clockrate: 400, 450, 475, 500 MHz. (550 MHz, undocumented)
External links
- AMD-K6-III Processor AMD (archived)
- AMD K6-III-P Mobile Product Brief AMD (archived)
- AMD K6-III+ Mobile Product Brief AMD (archived)
- IA-32 implementation: AMD K6 (K6, K6-2, and K6-III) at sandpile.org
- Socket 7: Fit For Years To Come! at Tom's Hardware
- Recipe For Revival: K6-2+ at AcesHardware.Com
- K6-III+: Super-7 to the Limit at AcesHardware.Com
- CPU Upgrade: Getting the AMD K6-2+ / K6-III+ to work on your Super Socket 7 board
- K6Plus.Com Overclockers Database
- Overclockers.Com CPU Database
- Pictures of AMD-K6-III chips at CPUShack.com
- Technical overview of the AMD-K6 series
- www.k6plus.com Enthusiasts which work even nowadays with K6-x+
- Central Tweaking Unit by Rob Mueller, allows use of Framebuffer (MTTR)& Write-Combining for K6-x CPUs