It has to be 100/100 X6. All P3 not being Tulatin cores are 100MHZ. Older series, like the 450-500 are 66-75MHZ. Heck, my CPU will do 75, 100 or even 112MHZ.
well i put the 800mhz processor in the comp i found yesterday and now nothing comes on the screen even with using the 600mhz ive checked everything possible (ram, cpu, i tried 3 vid cards, tried another processor, power cables, ide cables, hard drives, cd drive, EVERYTHING )