• Model 6
  • Littlefoot (Model 7)

The AMD K6 is an x86 microprocessor company AMD (Advanced Micro Devices ) and was originally developed by the company under the name NexGen Nx686. He is regarded as the main competitor to the Intel Pentium MMX or Pentium II and additionally competed with the Cyrix 6x86MX.

  • 3.1 K6 (Model 6)
  • 3.2 K6 ( Little Foot / Model 7)


As part of the acquisition of NexGen by AMD of the Nx686 was adapted to the Socket 7 and received Intel's MMX technology - the AMD K6 originated. The development of both processors, so the Nx686 and the K6 was Vinod Dham, who is regarded as the "father of the Pentium " instrumental. The K6 was the first serious competitor from AMD to Intel's Pentium processors developments and was first positioned as an alternative to Pentium MMX. After the release of the Pentium II, AMD had to contend with faster models against this new generation.



The K6 marks the use of a new generation of processors, the first model he himself was. There are three stages of development of this generation: the actual K6 (166 MHz to 300 MHz ) and its successor K6 -2 ( 266-550 MHz, with 3DNow technology! ) And K6 -III ( 400 and 450 MHz, with integrated L2 cache). The K6 itself consists of two models, which differ primarily by the manufacturing process and therefore also by the maximum clock frequency and operating voltage and as a result, the maximum power dissipation.


Since it is based on a NexGen design, the K6 has almost nothing in common with its predecessor K5, although both were constructed or developed internally RISC processor.


The K6 processors "Model 6" require an I / O voltage ( VIO ) of 3.3 V. With sufficient cooling, a K6 233 MHz VCore = 3.2V (Model 6) with Vcore = 3.3 V be operated. This operation is possible on Socket 7 motherboards that do not represent divided voltage supply ( Vcore / VIO ) for the CPU ready. Such motherboards also usually allow only selects the multiplier from 1.5 to 3.0 by means of two jumpers or DIP switches. With this, the K6 233 MHz only operate with a maximum of 200 MHz. A multiplier of 1.5 is, however, as interpreted by the K6 3.5 when only two jumpers or DIP switches are provided for setting and thus maximum multiplier, a multiplier of 3.0 is adjustable. Thus can the K6 233 MHz on these old motherboards with maximum allowable clock frequency to operate, however the voltage regulator for the CPU voltage usually requires a generously sized, extra cooling.


In retrospect, the K6 and its derivatives in terms of performance were a double-edged sword for AMD. Due to its slow (because running without pipeline ) floating point unit of the K6 against its direct competitor, the Intel processors Pentium MMX and Pentium II, for the FPU - intensive applications such as the then-emerging 3D games has no chance. On top of that, the Pentium II on fast L2 cache was able to draw directly on the processor module, whereas the processors of the K6 and K6- 2 series used as before the L2 cache of the ( super) Socket 7 motherboards. This bandwidth disadvantage made ​​to create the AMD CPUs, only the K6- III and the mobile variants K6 -2 and K6- III ran at the end of the K6- era thanks to the The integrated Level 2 cache in top form. These clearly show the advantages of the K6 architecture: A fast integer unit with a very short pipeline, an intelligent branch prediction unit and a very large for its time translation lookaside buffer gave it a high efficiency ( instructions per cycle). In a test against the successor - K7 architecture at the same clock speed of the K6 -2 was the winner in many integer -heavy benchmarks. However, while the only six-stage integer pipeline made ​​the K6 design largely independent of software optimizations, limited this low-latency design on the other hand significantly the maximum clock frequency: The K6 architecture reached at 570 MHz maximum, however, the K7 successor design scaled over the years to well over 2 GHz.

Model data

K6 (Model 6)

  • L1 - Cache: 32 32 KiB ( Data Instructions )
  • MMX
  • Socket 7 with 66 MHz
  • Release Date: April 2, 1997
  • Operation voltage ( Vcore ): 2.9 V (233 MHz: 3.2 V ) K6 233 MHz (Model 6) and 3.2 V
  • Manufacturing Technology: 0.3 micron
  • The size: 162 mm ² and 157 mm ² at 8.8 million transistors
  • Clock rates (power ): 166 MHz ( 17.2 W)
  • 200 MHz ( 20.0 W)
  • 233 MHz ( 28.3 W)

K6 ( Little Foot / Model 7)

  • L1 - Cache: 32 32 KiB ( Data Instructions )
  • MMX
  • Socket 7 with 66 MHz
  • Operation voltage ( Vcore ): 2.2V
  • Release Date: January 6, 1998
  • Manufacturing Technology: 0.25 micron
  • The size: 68 mm ² at 8.8 million transistors
  • Clock rates (power ): 200 MHz ( 12.45 W)
  • 233 MHz ( 13.50 W)
  • 266 MHz ( 14.55 W)
  • 300 MHz ( 15.40 W)