I managed to hit 3GHz (300x10) on my Sempy tonight and successfully passed a Memtest from an Ubuntu 7.10 x64 live cd, but XP won't boot. Brought it down to 2.5GHz and still nothing. The text-based progress bar loads slower than usual, then freezes at 100%. Specs are: AMD Sempy 64 3400+ Sck754 DFI LanParty UT nForce3 250gb 2xSeagate Barracuda 7200.10 250GB SATA (nForce RAID) Windows XP 64-bit 300FSB x3 HTT (900MHz) x10 Multi 1.78v CPU VID 1.8v Chipset VID 2.9v Mem VID ~DDR400 3-3-3-8-10-12 2T (effective. DDR-266 divider) Any tips? I needed a small voltage bump to hit 3GHz, so I'm thinking maybe I need another small bump to make it stable. The other idea is that despite the memory divider, the memory can't handle something (I have no idea what). I constantly had to set my divider down (sub DDR-400) the higher I went. Eventually, despite running sub-stock speeds, had to pull some of my memory out to reach 3GHz.