Motherboard: ASrock 770 extreme3
CPU: AMD Athlon II x3 550
Heatsink: Zalman CNPS9700
PSU: Corsair CMPSU-550VX (550W)
RAM: 4GB Corsair XMS3 DDR3 1600
HDD: 1TB Samsung Spinpoint F3
Video Card: ATI Radeon HD 5670 1GB
OS: Windows 7 64-bit
A few things you should know:
I did, in fact, unlock the fourth core on the CPU, but when I did this I ran a torture test on Prime95 for several hours with no errors. Also, with the heatsink I installed (I went way overkill on the heatsink), heat is not a problem.
After a week of running fine, my aunt (person I built the PC for) was playing Free Cell (of all things...) and the comp "popped" and shut down. My uncle entered the room and tried turning back on. The comp "popped" again and began smoking. This is all second-hand information (this is coming from my aunt's description) so I am sorry I cannot be more specific. I went over this evening to investigate (of course I will be blamed). The circuit burn smell seemed to be coming from the PSU, but I can't be sure. The PC will not turn on at all anymore. Essentially, my questions are as follows:
1.) Is this a PSU failure?
2.) How much damage can I expect? (Just PSU, motherboard and PSU, or mobo, PSU, and CPU?)
3.) Why would this happen? Especially after a week of no issues. The comp was under no stress (Free Cell!!!) and my aunt/uncle reported no power outage or noticeable surge in the lights or anything. Could it be just a bad PSU?
I plan on swapping out the PSU tomorrow and see if I can get the thing to start. Any preliminary input is much appreciated, as I would like some piece of mind on this matter before I go to bed.
Shouldn't my PSU choice have worked anyways though? Allocating the draw to different components shouldn't have made a difference (multiple versus single rails). Do multiple rails provide a fail safe or something?
1) Possible, but I would breakdown the PC into it's components to visually inspect them.
2) Unknown, but see #1. The components my seem fine, but can actually be damaged.
3) It's a fluke, it simply happens. Even the best of the best PSU or other component can have these type of flukes.
If you need to buy another PSU I recommend a good brand and model.
Corsair is a good brand, their PSUs are manufactured by CWT (Channel Well) and Seasonic. The Corsair VX-550 is made by CWT and has a good reputation as a manufacturer. I personally would not have an issue sticking in another VX-550 in your PC since CWT has a good rep.
Emerald's suggestion of the Antec BP550 is decent. It is manufactured by Delta which also has a pretty good reputation as well. I would say about on par with CWT. However, I can't shake the feeling that Antec cut corners on the design of the PSU. Antec was so much better in the past when they actually designed and manufactured their own PSUs.
My own personal recommendation is the Seasonic S12 520w PSU for $60 + $10 shipping. They are basically the premier manufacturer of PSUs; on a tier of their own. They manufacture some PSUs for Antec, Corsair, PC Power & Cooling, and XFX (all of them).
Regardless of what PSU you purchase (I do think the PSU went bad), your system might have some instability due to possible electrical surge. That's even if all components look fine so take the time to test the computer once you rebuild it.