Why can I just overclock the original processor, or a Pentium III processor?
The only known way of doing any processor overclocking on these machines is running a Celeron processor at 100 MHz FSB as mentioned earlier. All processors made since midway through the Pentium II era (which probably includes most or all of the ones that came in these machines originally) are multiplier-locked, so the CPU will only run at the multiple of the FSB speed that it is designed and tested to run at. The only other way of overclocking a Pentium II or Pentium III would be to increase the FSB speed past 100 MHz. However, this does not appear to be possible on this board. The clock generator chip on my system’s board is a Cypress 48C101-01, its datasheets are available here. (It’s a rectangular chip, mounted on the right side of the board in the area of the AGP slot, next to a small silver can which is presumably the clock crystal itself.) This data reveals that this chip’s FSB setting is set based solely on the signals received from the processor slot, so it is not changeable th