I just got my 1900 xp chip in the mail, I installed it, hooked everything back up and booted. Windows loads, stays stable for approxametly(sp?) 10 seconds and reboots...process repeats. I turn the cpu speed down to 1200 mhz(default values are 1200 and 1600 mhz) and it runs like a charm. My problem is the 1900 chip is a 1600 mhz chip. My thoughts go to PSU, i have a 350w, but i am running 7 fans inside plus the cpu fan. Could upgrading the PSU help, or is it something else? My mobo is jumperless so FSB, and multiplier's are all done in bios.