OK, so I built my computer about a week ago, and started OCing yesterday.
Phenom ii x4 955BE
MSI 880GM E-41
Silverstone Essentials 400W
So heres the situation: In the process of OCing, I had the FSB and multiplier set to 208x20.5, and was upping the voltage in search of stability. I was moving upwards from the default setting about .1V at a time. Last setting used was 1.491V (BIOS setting), and CPUZ was reporting voltage fluctuating between 1.488, 1.496, and 1.502V. After every voltage increase I was booting into Windows 7 Pro and starting up Prime95 blend test, and running it until I got an error. Temps peaked at 54C after about 7 minutes of Prime95. At the previous voltage setting (1.481V) the 4th core produced an error after about 7 minutes. So after upping the voltage to 1.491V in the BIOS, I booted up and started Prime95; and then hopped into the shower. I got out about a half hour later and the computer had shut off completely. No fans, LEDs, blue screen, nothing. So I hit the power button and nothing happened. I have since tried the reset switch, clearing the CMOS data, removing and reinserting the motherboard battery, verifying that everything is correctly plugged in, and verifying that the power strip works. However, to no avail. If I turn the switch on the PSU off, then back on, and then hit the power button on the case, the fans and LEDs inside the case come on and then immediately shut off, being on for maybe half a second. Some other things I perhaps should mention: The peripherals are getting power, there is an LED inside my mouse, and it glows as long as the PSU switch is turned on, regardless of whether or not the computer is on or off. Also, I have case fans plugged directly into the PSU via 4 pin molex connectors (not 3 pin motherboard fan connectors), and those follow the same routine as the fans that have their power routed through the motherboard, a half second blip after turning it on, then nothing.
My first guess was that the motherboard died, however it shouldn't have as I had everything within specs; i.e. the CPU voltage was (well) below 1.5V, and it was only at 54C. Is this a PSU issue? if so, how is it that my mouse is getting power?
Another note - The CPU and motherboard were purchased together as a combo deal from Newegg. Meaning that if I return the motherboard, I must also return the CPU. And I would definitely not like to return the CPU, as it is (by all appearances) a considerably above average chip. If I end up having to return the motherboard and CPU, I may consider a different socket/CPU. Feel free to suggest your opinions on the Phenom ii x6 series as well as any other options (within the same price bracket ofc).
To accurately test a PSU, it is best to use a voltmeter (or multimeter). However, if you want see if your PSU can handle less load, then remove everything connected to the mobo, except for the PSU and the CPU/Heatsink. Jump the PWR_SW pins and see if the heatsink fan spins. If it does, shut down, and then add a stick of RAM. Jump the PWR_SW pins again. If successful, continue to add devices one at a time.
On a whim, I tried disconnecting the 4 pin CPU power connector. When I did, everything turned on. It obviously wouldn't post, but at least now I know that the problem is most likely the CPU. Why it died with only at MOST 1.5V (rated max is 1.55V) and peak temps 54C (rated max is 70C, safe max ~60C) I will never know. But hey, I feel confident that returning the motherboard and CPU (they came as a combo, so I must return both) is the correct move.
Next question: what to replace them with? another 955 or a 1055T or 1090T? or move to intel? If so, i3-2100 or i5-2400? or possibly an 1156 chip? I don't know...
From a cost savings perspective, replacing the 955 or upgrading to an X6 would be best. Still, it's a matter of workload; that is, what you'll be using the computer for. While a lot of software is (now) multithreaded, hardly any make use of all six cores.
If you were to Intel, you shouldn't get anything lower than an i5-2400; for consideration of performance vs. value (cheap, but sacrifices power/potential). The most common i5 is the 2500k for its OC potential. The i7's are only good for their support of triple channel (in my opinion, of course).