it depends on the processor
u said in ur other post u r running an 800 mhz, but of wat kind?
pentium 3, celeron, athlon, duron?
but ti also depends on your mobo, as the mobo is only designed to go so high
since i dont know i may as well suggest you go buy a whoel new mobo and processor, either a pentium 4 or AMD XP based on your budget(and you may have to get new ram too, assuming u currently use SD RAM, as these new boards use DDR)
if youre lookin for a cheap deal, i would suggest u go with amd, but only up to a 2400+, the bartons are rather pricey and dont perform as well compared to pentium 4s with HT
if you can afford it, buy a P4 with HT(make sure it is HT, as that makes a a fair difference in performance), the lowest P4 with HT i belive is 2.4 ghz, but i cannot confirm this atm