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{{Multiple issues|
{{Essay-like|article|date=December 2007}}
{{more citations needed|date=March 2016}}
{{lead rewrite|date=March 2014}}
⚫ }}
{{short description|Microprocessor series by AMD}}
{{Infobox CPU {{Infobox CPU
| name = K6-III, K6-2+ | name = K6-III, K6-2+
| image = Amd-k6-3.svg | image = Amd-k6-3.svg
| produced-start = February 1999 | produced-start = February 22, 1999
| produced-end = End of 2003<ref></ref>
| produced-end = 2000
| slowest = 350 | slow-unit = MHz | slowest = 333 | slow-unit = MHz
| fastest = 550 | fast-unit = MHz | fastest = 550 | fast-unit = MHz
| fsb-slowest = 66 | fsb-slow-unit = MHz | fsb-slowest = 66 | fsb-slow-unit = MHz
| fsb-fastest = 100 | fsb-fast-unit = MHz | fsb-fastest = 100 | fsb-fast-unit = MHz
| manuf1 = ] | manuf1 = ]
| core1 = Sharptooth | core1 = Sharptooth
| core2 = | size-from = 0.25μm
| core3 = | size-to = 0.18μm
| core4 = | arch = x86
| size-from = 0.25µm | microarch = ]
| size-to = 0.18µm
⚫ | arch = ], ], Enhanced 3DNow! (K6-III+)
| microarch = ]
| predecessor = ] | predecessor = ]
| successor = ] | successor = ]
| sock1 = ] | sock1 = ]
| sock2 = ] | sock2 = ]
| sock3 = | sock3 =
| sock4 = | sock4 =
| sock5 = | sock5 =
| numcores = 1 | numcores = 1
⚫ |extensions1=]|extensions2=]|extensions3=Enhanced 3DNow! (K6-III+)}}
⚫ }}
The '''K6-III''', code-named "Sharptooth", was an ] ] manufactured by ], released on 22 February 1999, with 400 and 450&nbsp;MHz models. It was the last ] desktop processor. For an extremely short time after its release, the fastest available desktop processor from Intel was the Pentium II 450&nbsp;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&nbsp;MHz, slightly faster than the K6-III 450&nbsp;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&nbsp;MHz K6-IIIs is claimed by Ars Technica to often outperform<ref></ref> the hugely higher-priced Pentium III "Katmai" 450- and 500-MHz models, respectively. The '''K6-III''' (code name: "Sharptooth") was an ] ] line manufactured by ] that launched on February 22, 1999. The launch consisted of both 400 and 450&nbsp;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 ] systems, however later mobile K6-III+ and K6-2+ processors could be run unofficially in certain socket 7 motherboards if an updated ] was made available for a given board. The ] processor from Intel launched 6 days later.

At its release, the fastest available desktop processor from Intel was the Pentium II 450&nbsp;MHz, and in integer application benchmarks a 400&nbsp;MHz K6-III was able to beat it as the fastest processor available for business applications.<ref>{{Cite web|url=https://www.theregister.co.uk/1999/02/24/intel_pentium_iii_vs_amd/|title=Intel Pentium III vs. AMD K6-III – the benchmarks|website=] }}</ref> Just days later on February 26 Intel released the ] line at speeds of 500&nbsp;MHz, slightly faster than the K6-III 450&nbsp;MHz.

Intel retained the lead in 3D gaming performance. Many popular ] games at the time were specifically tuned to extract maximum performance from Intel's ] floating point unit in drawing their 3D environments. Since the K6-III inherits the same floating point unit as the K6-2 (low latency but not pipelined), unless the game was updated to use AMD's 3D-Now! ] instructions - performance could still remain significantly lower than when run on Intel.


==Architecture== ==Architecture==
] ]
In conception, the design is simple: it was a ] with on-die L2 ]. 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&nbsp;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.{{Citation needed|date=July 2007}} In conception, the design is simple: it was a ] with on-die 256KiB L2 ]. 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&nbsp;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.<ref> by Anand Lal Shimpi on anandtech.com</ref>


===3DNow!=== ===3DNow!===
Line 37: Line 42:
{{ details|3DNow! }} {{ details|3DNow! }}


3DNow! is an extension to the x86 ] developed by ] (AMD). It added ] (SIMD) instructions to the base x86 instruction set, enabling it to perform ], which improves the performance of many graphic-intensive applications. The first microprocessor to implement 3DNow was the ], which was introduced in 1998.
A single instruction multiple data (]) 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.

The K6-III+ had the "Enhanced 3DNow!"(Extended 3DNow! or 3DNow+) which added 5 new ] instructions, but not the 19 new extended MMX instructions.


===TriLevel Cache=== ===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. 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.

<gallery mode="packed" heights="150px">
AMD@180nm@K6@Model13 - (cpuid5D0)@AMD-K6-III+ 400ATZ@1.6V CORE A 0336WPBW 1999 AMD DSCx8 polysilicon@macrolens.jpg|Die shot of an AMD K6-III+ 400ATZ processor
AMD@250nm@K6@Model9(sharptooth) - (cpuid591)@AMD-K6-III 450AHX@2.4V CORE B 9931FPDW 1998 AMD DSCx8 polysilicon@macrolens.jpg|Die shot of an AMD-K6-III 450AHX processor
</gallery>


==Market performance== ==Market performance==
Intel's Pentium II replacement was not yet available but, as a stop-gap, Intel introduced a modestly revised version of the ] and re-badged it as the "]". The base design was unchanged (the addition of ] 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{{Who|date=March 2009}} 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. Intel's Pentium II replacement was not yet available but, as a stop-gap, Intel introduced a modestly revised version of the ] and re-badged it as the "]". The base design was unchanged (the addition of ] 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.


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&nbsp;MHz or faster K6-III after the rare 500&nbsp;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 ] instead. Intel produced a 550&nbsp;MHz Pentium III with some success but their 600&nbsp;MHz version had reliability issues and was soon recalled. 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&nbsp;MHz or faster K6-III after the rare 500&nbsp;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 ] instead. Intel produced a 550&nbsp;MHz Pentium III with some success but their 600&nbsp;MHz version had reliability issues and was soon recalled.


With the release of the ], 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: in spite of its 21.4 million transistors, its 118 mm² die was considerably smaller than the 184 mm² of the 22-million-transistor Athlon (cache RAM taking much less area per-transistor than logic), but the K6-III was still significantly more costly to produce than the 81 mm² 9.3 million-transistor K6-2 CPUs. (roughly 2/3 the size of the K6-III) For a time, the K6-III was a low priority part for AMD&mdash;something to be made only when all orders for high-priced Athlons and cheap-to-produce K6-2s had been filled&mdash;and it became difficult to obtain in significant quantities. With the release of the ], 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: in spite of its 21.4 million transistors, its 118&nbsp;mm² die was considerably smaller than the 184&nbsp;mm² of the 22-million-transistor Athlon (cache RAM taking much less area per-transistor than logic), but the K6-III was still significantly more costly to produce than the 81&nbsp;mm² 9.3 million-transistor K6-2 CPUs (roughly 2/3 the size of the K6-III). For a time, the K6-III was a low priority part for AMD&mdash;something to be made only when all orders for high-priced Athlons and cheap-to-produce K6-2s had been filled&mdash;and it became difficult to obtain in significant quantities.


The original K6-III went out of production when Intel released their "]" 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). The original K6-III went out of production when Intel released their "]" 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+ === === 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&nbsp;KiB cache, the III+ with the full 256 KiB) made on a new 180&nbsp;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 ] power saving technology. Essentially, the power savings were achieved with a combination of frequency (through adjusting multipliers) and voltage reduction. By the time the x86 CPU shortage was over, AMD had developed and released revised members of the K6 family. These K6-2+ and K6-III+ variants were specifically designed as low-power mobile (laptop) CPUs, and significantly marked the transition of the K6 architecture (and foretold of AMD's future K7 project) to the new 180&nbsp;nm production process. Functionally, both parts were die shrunk K6-IIIs (the 2+ disabled 128&nbsp;KiB of cache, the III+ had the full 256 KiB) and introduced AMD's new ] power saving technology. PowerNow! offered processor power savings for mobile applications by measuring computational load, and reduced processor operational voltage and frequency during idle periods in order to reduce overall system power consumption.


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&nbsp;MHz CPUs routinely overclocked to almost 600&nbsp;MHz. Unfortunately, even with the 180&nbsp;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&nbsp;GHz clock speed, K6 III+ and 2+ never clocked higher than 570&nbsp;MHz officially, with ] using air cooling achieving around 800&nbsp;MHz at best. Although intended for notebook computers, both parts found an enthusiast following also in desktop systems as some motherboard companies (such as Gigabyte and FIC) provided ] updates for their desktop motherboards to allow usage of these processors. For other officially not supported mainboards, the enthusiast community created ] on their own.<ref> by Ondrej Zary on rainbow-software.org</ref><ref> {{Webarchive|url=https://web.archive.org/web/20200716224049/http://www.ryston.cz/petr/bios/ |date=2020-07-16 }} by Petr Soucek on ryston.cz</ref><ref> {{Webarchive|url=https://web.archive.org/web/20210211064357/http://web.inter.nl.net/hcc/J.Steunebrink/k6plus.htm |date=2021-02-11 }} by Jan Steunebrink on inter.nl.net</ref> These boards became firm favorites within the ] community. Both the K6-III+ and K6-2+ 450&nbsp;MHz CPUs were routinely overclocked to over 600&nbsp;MHz ({{nowrap|112 × 5.5 {{=}} 616}}). Unfortunately, even with the 180&nbsp;nm process shrink, the K6 architecture's short 6-stage pipeline while efficient, was difficult to scale with regards to clock speed. K6 III+ and 2+ were never offered higher than 570&nbsp;MHz officially, and ] efforts using air cooling achieved a maximum around 800&nbsp;MHz (133x6) at best - however this constraint was also exacerbated by a lack of Socket 7 motherboards supporting stable speeds over 112&nbsp;MHz ].

As AMD's marketing resources at the time were focused on the launch of the upcoming Athlon K7 processor line, the 180&nbsp;nm K6 series were relatively unknown outside of the industry.

== Features ==
{{empty section|date=March 2023}}


== Models == == Models ==
===K6-III ("Sharptooth", K6-3D+, 250 nm)=== ===K6-III ("Sharptooth", K6-3D+, 250 nm)===
] ]
] AMD K6-III]]
* CPU ID: AuthenticAMD Family 5 Model 9 * CPU ID: AuthenticAMD Family 5 Model 9
* L1-Cache: 32 + 32 KiB (Data + Instructions) * L1-Cache: 32 + 32 KiB (Data + Instructions)
* L2-Cache: 256 KiB, fullspeed * L2-Cache: 256 KiB, full speed
* ], ] * ], ]
* ], ] * Socket 7, ]
* ]: 66/100, 100&nbsp;MHz * ]: 66/100, 100&nbsp;MHz
* VCore: 2.2 V, 2.4 V * VCore: 2.2 V, 2.4 V
* First release: February 22, 1999 * First release: February 22, 1999
* Manufacturing process: 0.25&nbsp;µm * Manufacturing process: 0.25&nbsp;μm
* Clockrate: 400, 450&nbsp;MHz * Clockrate: 333, 400, 450&nbsp;MHz


===K6-III-P (250 nm, mobile)=== ===K6-III-P (250 nm, mobile)===
* CPU ID: AuthenticAMD Family 5 Model 9 * CPU ID: AuthenticAMD Family 5 Model 9
* L1-Cache: 32 + 32 KiB (Data + Instructions) * L1-Cache: 32 + 32 KiB (Data + Instructions)
* L2-Cache: 256 KiB, fullspeed * L2-Cache: 256 KiB, full speed
* ], ] * ], 3DNow!
* ], ] * Socket 7, Super7
* ]: 66, 95, 96.2, 66/100, 100&nbsp;MHz * ]: 66, 95, 96.2, 66/100, 100&nbsp;MHz
* VCore: 2.0 V, 2.2 V * VCore: 2.0 V, 2.2 V
* First release: May 31, 1999 * First release: May 31, 1999
* Manufacturing process: 0.25&nbsp;µm * Manufacturing process: 0.25&nbsp;μm
* Clockrate: 350, 366, 380, 400, 433, 450&nbsp;MHz * Clockrate: 350, 366, 380, 400, 433, 450, 475&nbsp;MHz


===K6-2+ (180 nm, mobile)=== ===K6-2+ (180 nm, mobile)===
] ]
* CPU ID: AuthenticAMD Family 5 Model 13 * CPU ID: AuthenticAMD Family 5 Model 13
* L1-Cache: 32 + 32 KiB (Data + Instructions) * L1-Cache: 32 + 32 KiB (Data + Instructions)
* L2-Cache: 128 KiB, fullspeed * L2-Cache: 128 KiB, full speed
* ], Extended ], ] * ], Extended 3DNow!, ]
* ] * Super Socket 7
* ]: 95, 97, 100&nbsp;MHz * Front side bus: 95, 97, 100&nbsp;MHz
* VCore: 2.0 V * VCore: 2.0 V
* First release: April 18, 2000 * First release: April 18, 2000
* Manufacturing process: 0.18&nbsp;µm * Manufacturing process: 0.18&nbsp;μm
* Clockrate: 450, 475, 500, 533, 550&nbsp;MHz. (570&nbsp;MHz, undocumented) * Clockrate: 450, 475, 500, 533, 550&nbsp;MHz. (570&nbsp;MHz, undocumented)


===K6-III+ (180 nm, mobile)=== ===K6-III+ (180 nm, mobile)===
] ]
* CPU ID: AuthenticAMD Family 5 Model 13 * CPU ID: AuthenticAMD Family 5 Model 13
* L1-Cache: 32 + 32 KiB (Data + Instructions) * L1-Cache: 32 + 32 KiB (Data + Instructions)
* L2-Cache: 256 KiB, fullspeed * L2-Cache: 256 KiB, full speed
* ], Extended ], ] * ], Extended 3DNow!, PowerNow!
* ] * Super7
* ]: 95, 100&nbsp;MHz * Front side bus: 95, 100&nbsp;MHz
* VCore: 2.0 V, (1.6 V, 1.8 V low voltage types) * VCore: 2.0 V, (1.6 V, 1.8 V low voltage types)
* First release: April 18, 2000 * First release: April 18, 2000
* Manufacturing process: 0.18&nbsp;µm * Manufacturing process: 0.18&nbsp;μm
* Clockrate: 400, 450, 475, 500&nbsp;MHz. (550&nbsp;MHz, undocumented) * Clockrate: 400, 450, 475, 500&nbsp;MHz. (550&nbsp;MHz, undocumented)


== References == == References ==
{{reflist}} {{Reflist|30em}}


== External links== == External links ==
{{Commons category}} {{Commons category|AMD K6-III}}
* AMD (archived) * AMD (archived)
* AMD (archived) * AMD (archived)
* AMD (archived) * AMD (archived)
⚫ * at Tom's Hardware
* at sandpile.org
⚫ * at AcesHardware.Com (archived)
⚫ * at Tom's Hardware
* at AcesHardware.Com (archived) * at AcesHardware.Com (archived)
⚫ * at AcesHardware.Com (archived)
*
*
*
*
*
*
*


{{AMD processors}} {{AMD processors}}


] ]
]
]

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Microprocessor series by AMD
K6-III, K6-2+
General information
LaunchedFebruary 22, 1999
DiscontinuedEnd of 2003
Common manufacturer
Performance
Max. CPU clock rate333 MHz to 550 MHz
FSB speeds66 MHz to 100 MHz
Architecture and classification
Technology node0.25μm to 0.18μm
MicroarchitectureK6
Instruction setx86
Extensions
Physical specifications
Cores
  • 1
Sockets
Products, models, variants
Core name
  • Sharptooth
History
PredecessorK6-2
SuccessorAthlon

The K6-III (code name: "Sharptooth") 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.

At its release, the fastest available desktop processor from Intel was the Pentium II 450 MHz, and in integer application benchmarks a 400 MHz K6-III was able to beat it as the fastest processor available for business applications. Just days later on February 26 Intel released the Pentium III "Katmai" line at speeds of 500 MHz, slightly faster than the K6-III 450 MHz.

Intel retained the lead in 3D gaming performance. Many popular first person games at the time were specifically tuned to extract maximum performance from Intel's pipelined floating point unit in drawing their 3D environments. Since the K6-III inherits the same floating point unit as the K6-2 (low latency but not pipelined), unless the game was updated to use AMD's 3D-Now! SIMD instructions - performance could still remain significantly lower than when run on Intel.

Architecture

The AMD K6-III architecture.

In conception, the design is simple: it was a K6-2 with on-die 256KiB 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.

3DNow!

Further information: 3DNow!

3DNow! is an extension to the x86 instruction set developed by Advanced Micro Devices (AMD). It added single instruction multiple data (SIMD) instructions to the base x86 instruction set, enabling it to perform vector processing, which improves the performance of many graphic-intensive applications. The first microprocessor to implement 3DNow was the AMD K6-2, which was introduced in 1998.

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.

  • Die shot of an AMD K6-III+ 400ATZ processor Die shot of an AMD K6-III+ 400ATZ processor
  • Die shot of an AMD-K6-III 450AHX processor Die shot of an AMD-K6-III 450AHX processor

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 II 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.

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: in spite of its 21.4 million transistors, its 118 mm² die was considerably smaller than the 184 mm² of the 22-million-transistor Athlon (cache RAM taking much less area per-transistor than logic), but the K6-III was still significantly more costly to produce than the 81 mm² 9.3 million-transistor K6-2 CPUs (roughly 2/3 the size of the K6-III). 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 and released revised members of the K6 family. These K6-2+ and K6-III+ variants were specifically designed as low-power mobile (laptop) CPUs, and significantly marked the transition of the K6 architecture (and foretold of AMD's future K7 project) to the new 180 nm production process. Functionally, both parts were die shrunk K6-IIIs (the 2+ disabled 128 KiB of cache, the III+ had the full 256 KiB) and introduced AMD's new PowerNow! power saving technology. PowerNow! offered processor power savings for mobile applications by measuring computational load, and reduced processor operational voltage and frequency during idle periods in order to reduce overall system power consumption.

Although intended for notebook computers, both parts found an enthusiast following also in desktop systems as some motherboard companies (such as Gigabyte and FIC) provided BIOS updates for their desktop motherboards to allow usage of these processors. For other officially not supported mainboards, the enthusiast community created unofficial BIOS updates on their own. These boards became firm favorites within the overclocking community. Both the K6-III+ and K6-2+ 450 MHz CPUs were routinely overclocked to over 600 MHz (112 × 5.5 = 616). Unfortunately, even with the 180 nm process shrink, the K6 architecture's short 6-stage pipeline while efficient, was difficult to scale with regards to clock speed. K6 III+ and 2+ were never offered higher than 570 MHz officially, and overclocking efforts using air cooling achieved a maximum around 800 MHz (133x6) at best - however this constraint was also exacerbated by a lack of Socket 7 motherboards supporting stable speeds over 112 MHz FSB.

As AMD's marketing resources at the time were focused on the launch of the upcoming Athlon K7 processor line, the 180 nm K6 series were relatively unknown outside of the industry.

Features

This section is empty. You can help by adding to it. (March 2023)

Models

K6-III ("Sharptooth", K6-3D+, 250 nm)

AMD K6-III 400 MHz Microprocessor
A delidded AMD K6-III
  • CPU ID: AuthenticAMD Family 5 Model 9
  • L1-Cache: 32 + 32 KiB (Data + Instructions)
  • L2-Cache: 256 KiB, full speed
  • MMX, 3DNow!
  • Socket 7, Super7
  • Front side bus: 66/100, 100 MHz
  • VCore: 2.2 V, 2.4 V
  • First release: February 22, 1999
  • Manufacturing process: 0.25 μm
  • Clockrate: 333, 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, full speed
  • MMX, 3DNow!
  • Socket 7, Super7
  • Front side bus: 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, 475 MHz

K6-2+ (180 nm, mobile)

AMD K6-2+ 475 MHz Microprocessor
  • CPU ID: AuthenticAMD Family 5 Model 13
  • L1-Cache: 32 + 32 KiB (Data + Instructions)
  • L2-Cache: 128 KiB, full speed
  • MMX, Extended 3DNow!, PowerNow!
  • Super Socket 7
  • Front side bus: 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)

AMD K6-III+ 550 MHz Microprocessor
  • CPU ID: AuthenticAMD Family 5 Model 13
  • L1-Cache: 32 + 32 KiB (Data + Instructions)
  • L2-Cache: 256 KiB, full speed
  • MMX, Extended 3DNow!, PowerNow!
  • Super7
  • Front side bus: 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)

References

  1. AMD to kill K6, K6-II, K6-III
  2. "Intel Pentium III vs. AMD K6-III – the benchmarks". The Register.
  3. AMD K6-3 Review - Windows 98 Performance Comparison by Anand Lal Shimpi on anandtech.com
  4. M577 BIOS 03/06/1999 with K6-2+/III+ & HDD up to 128GB by Ondrej Zary on rainbow-software.org
  5. Award BIOS Modifications Archived 2020-07-16 at the Wayback Machine by Petr Soucek on ryston.cz
  6. K6plus Archived 2021-02-11 at the Wayback Machine by Jan Steunebrink on inter.nl.net

External links

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