High Performance Thanks to 83 MHz System Clock
When the Pentium and Pentium MMX were popular, the maximum system clock was 66 MHz. For those CPUs the L2 cache resides on a Socket7 board and not on the die of the processor. As a consequence, the L2 cache and the system memory are accessed at system clock frequency. In order to run a modern K6-2+ at 500 MHz, it is necessary to set the system clock above the official specification. On most boards the jumper settings are noted for all clock rates up to 75 MHz. The highest possible clock rates of the P55T2P4 series are 83 MHz and with this frequency the highest performance is achieved. We must clearly point out here that in this case the PCI bus as well as the ISA interface are significantly overclocked. Because of the higher PCI clock of 41.5 MHz (instead of the default 33 MHz) some older graphics cards might run into problems. A Riva 128 graphics card in combination with two Voodoo2 cards (SLI mode) are an ideal solution. The undocumented settings for a system clock of 83 MHz are listed in the bottom table. The system clock value of 108 MHz, which is also listed, has no meaning in practice because the system refuses to boot at this frequency.
|68 MHz||1-2||1-2||1-2||turbo mode|
|75 MHz||1-2||2-3||1-2||runs very stable|
|83 MHz||1-2||1-2||2-3||runs stable|
|108 MHz||2-3||1-2||1-2||not working|