Oy All. Here goes : Pc won't boot anymore, unless i max. Vcore voltage and up FSB voltage, and lower FSB/CPU freq. Rebooting constantly if at stock speed/voltages with the occational bluescreen. Seems to be getting gradually worse and worse. Btw. Pc have been running for 1½ Yrs. on an underpowered PSU (not anymore though, got me a Corsair TX650, installed it, and the pc ran fine at stock speed/voltage for about 2 days, then reverted to rebooting if running at stock). And yes, 1½ Yrs. is alot .. I was convinced it was vista 64bit killing me .. But no. HDD is Ok - RAM is Ok - Gfx/Gpu is Ok - PSU is Ok (voltages and amps are more than ample / minimal ripple) - Software/BIOS (+BIOSsettings) is Ok - Temps is Ok - Tested Vista 64Bit / Win2k / XpPro 32Bit with no difference (various HDD's). Have cleared CMOS - Disconnected all hardware, reinstalled 1 by 1 in different combo's - No visible loose connections or burnmarks anywhere. Addition : Pc will boot @ 2,4 GHz (stock 3GHz) @ norm voltages and remain close to stable. Could the BIOS Speedstep setting (minimal/automatic/disabled) minimal (when set to minimal cpu runs @ 2.4GHZ), be interferring with the MOBO/CPU ? (normally running with speedstep and c1 disabled, and maxed high performance power scheme). Now, im thinking it's either the CPU or MOBO messing with me, but those are hard to test/errorcheck .. Aren't they ? Any suggestions are greatly appreciated, as im almost out of ideas (ye, i know that i could "just" get another CPU/MOBO to test with, but the lack of cash u know .. ) Take Care Outthere.