I o/c 300Mhz to 400Mhz on 100FSB and it wouldnt boot. but it is stable @ 350Mhz though. after i ran 350Mhz for a while then i tried 400Mhz, i saw it boot up and my BIOS said 400Mhz then it just froze there so i reboot it and it just doesnt boot @ 400Mhz. i have a old .35 micron P2 and is it not enough voltage? i have it on 3.2v and thats the highest i can go on my BX-6. if i dont put it on that voltage windows would just restart automatically because its not stable sometimes. Its kinda high but it works...my system temp. is at 85F.