KarbosGuide.com. Module 3e.05

The AMD K6-3

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  • K6-3
  • K6-2+
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  • K6-3

    AMD announced the very powerful K6-3 for quite a long time. It was delayed quite a while, should have been released February 22nd 1999. During the delay Intel had time establish its Socket 370 version of Celeron. But finally it arrived in the summer of 1999.

    Using the next version of this chip - model 9 code name "Sharptooth" - you may have three levels of cache!

    In the K6-3 you find:

  • A slightly improved K6-2 unit.
  • An in-chip L2 cache of 256 KB.
  • TriLevel Cache design.
  • New 133 MHz Front side bus.
  • Clock speeds of 400 MHz and 450 MHz.

    TriLevel Cache design

    Both the 64 KB L1 cache and the 256 KB L2 cache are integrated with the chip. This L2 on-die cache works at full processor speed just like it did in the Pentium Pro, and as it does in the Celeron A and in the Xeon processors from Intel. This will definitely speed up the K6 quite a bit!

    Since the K6-3 is to be used in a Super 7 motherboard there is room for another level of cache, the L3 cache. The TriLevel Cache design is constructed to use the existing motherboards with up to 2 MB of cache on-board. This used-to-be L2 cache (on the motherboard) is used as the third level of cache. This happens automatically, and the bigger cache seems to increase performance a lot!

    High performance

    Tests show performance from the K6-3 450 MHz comparable to the Pentium III 500 MHz processor. This is coming from a Socket 7 motherboard! My prediction is that the K6-3 will be an excellent CPU at a very good price. The problem was to find it, the K6-3 never became very popular.

    Still weaknesses in the FPU

    Traditionally only Intel can produce a powerful FPU (Floating Point Unit). Test confirms that the K6-3 has the same FPU as the K6-2 does. At same clock frequencies it performs 40% under the Pentium III. However the 3DNow! technology, which is supported by the Microsoft DirectX software layer, makes up for the weak traditional FP-performance. In test it ends up 15% under the equaling Pentium III.

    The die size

    The K6-3 obviously is bigger than the K6-2, due to the integrated L2 cache. However it is a lot smaller than the Athlons :

    Die size
    81 mm2
    118 mm2
    K7 Athlon 0.25 micron
    184 mm2
    K7 Athlon 0.18 micron
    100 mm2
    Intel Pentium III Cumine
    106 mm2


    In 2000 the K6-3 is expected to disappear from the market. It never became a success. However, the K6-2 has been a great seller, so AMD will launche new versions of the K6-3 as K6-2+.

    This new chip will have following features:

  • 0.18 micron process technology
  • Integrated 256 KB L2 cache
  • Additional 3DNow! instructions (from Athlon)
  • 550 MHz

    The maximum speed from this design is expected to be 750 MHz. Hence one can expect the Socket7 platform soon to die out.

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    Learn more

    Read about chip sets on the motherboard in module 2d

    Read more about RAM in module 2e

    Read module 5a about expansion cards, where we evaluate the I/O buses from the port side.

    Read module 5b about AGP and module 5c about Firewire.

    Read module 7a about monitors, and 7b on graphics card.

    Read module 7c about sound cards, and 7d on digital sound and music.

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