166 FSB!! thats 333 DDR!! i tried 167 but my comp screwed up. I was only able to hit this with a socket A cooler rated at 1.5 GHz and silver past. Looks like i have 2 cpu's now . Also this improves my cpu overclock by 2 MHz hehe now it's 1577. But don't wory i also cooled my ram! and i used crappy pc2100 (not exactly your crucial)