New PC build worked fine for weeks, sudden random shut downs

[Wesdawg]

I know it's kind of a long thread, but please read! I'M DESPERATE!
I recently built a new PC. Here are the specs:
-AMD FX-4100 x4 3.6ghz (3.8ghz turbo)
-Cooler Master Elite 431 ATX Mid-Tower Case
-Corsair TX650 PSU 650W
-ASUS M5A88-V Evo AM3+
-G.Skill RipJaws RAM (2x4GB)
-Radeon HD 6750 DDR5 1GB

Got a Blu-ray drive and a DVD+/- RW Drive in there as well, along with a 200gb Seagate Barracuda HDD. (Not a good choice, I know, but a new hard drive didn't fit the budget so I used my friend's old HDD).

Here's the problem: It worked fine for a couple weeks. Then I installed Far Cry 3 and found out I couldn't play it on Ultra settings, so I tried overclocking the GPU. Not the CPU, as I had core unlocker and turbo core enabled in the BIOS. Whenever I played any kind of high quality video after overclocking it would freeze, no matter how I O.C.'d, so I said "forget it".

After playing Far Cry 3 for awhile, I tried playing League of Legends, a game that is a cakewalk for my computer as I played it before at 60+ FPS. When I entered a game it was laggy, the resolution looked wrong, even though the settings were all right, and the FPS was around 40. At that point I began to uninstall and reinstall the game. While downloading League of Legends I was playing Far Cry 3, and a few hours had passed, and I eventually exited the game and began browsing the internet. A few minutes after browsing the internet, the computer just shut down. No BSOD or nothing, just instantly powered down.

After it turned off I tried turning it back on, and nothing. So I unplugged for 30, plugged back in and pressed the power button; the fans began to spin for a split second, and then nothing. Eventually I got it back on, but it turned off again a few minutes later. The next day I let it sit all day and turned it on again. It shut down the same way after awhile.

I've monitored my temps, checked to see if maybe overheating was causing the problem, everything checks out OK. I will admit I'm using the stock CPU fan and stock thermal paste pre-applied to the bottom of the fan. But it has shut down when the CPU is at 40 degrees Celsius.

It doesn't stop. It's always random. Sometimes I'll be able to use the thing for hours, other times for a couple minutes before it shuts down. Everytime I try to turn it back on it does the same thing that happened the first time. It only comes back on after sitting for awhile. I've unplugged everything from the MOBO other than the CPU/Fan, and power. I've reset the CMOS battery. It does the same thing no matter what.

Is there anything else you guys can think of?

 

[smorizio]

could be a few issues. could be you pushed the gpu card to far and it now overheating or just shorting out.check that the gpu fan is working. download msi afterburned watch the gpu temps and try turnign the fan speed to max and see if the system stays up. download hardware monitor and check that the power supply is holding the pc up. if your cpu or mb has onboard video or you have or a friend has another video card swap the video card then the power supply. also for testing undo any over clocking and make sure your mb bios and mb drivers are up to date.

 

[Wesdawg]

Like I said, I monitored the temps. The temperatures have nothing to do with when the PC turns off. It's turned off when they're all cool. I've monitored the voltages with as well and all seems as it should be. And also like I said I tried running it without the graphics card and everything. It still does the same thing. Turns off whenever it wants to. No warning at all. I even disabled the core unlocker, igpu enhancer, and turbo core. Nothing stops it.

EDIT: BIOS is up too date as well.

 

[smorizio]

then it going to be a power issue. power supply could be failing or there a bad cap on the mb.

 

[dodger46]

Did you try HW monitor to see if yr rail volts ok?

 

[Wesdawg]

I downloaded HW monitor. Everything seems to be OK, but I could be wrong.

 

[Daboydman]

Just a side note: I don't find it surprising at all that you can't play Far Cry 3 on ultra settings with a HD 6750. On low settings the HD 7750 gets 39 average FPS @ 1920x1080 (http://www.tomshardware.co.uk/far-cry-3-performance-benchmark,review-32584-4.html but I suppose we don't know what resolution you're playing at). Even so, asking a HD 6750 to try and play Far Cry 3 on ultra settings is ridiculous.

 

[Wesdawg]

I was playing at 1920x1080, so you were right on the money.

 

[Wesdawg]

OK, I updated my BIOS. I thought it was up to date, but there was a recent update last month. So I flashed the new BIOS. So far everything seems to be wroking fine, but it could turn off at anytime. I'll keep you guys updated.

 

[Wesdawg]

Aaand it turned off again. Any other ideas?

 

[ronintexas]

Generally this has to be one of two things - the mobo or the power supply. More often, it is the power supply - as the cpu load increases, more power is requested from the power supply, and it will shut down.

Do you have another power supply to try?

 

[Wesdawg]

Unfortunately, I do not.

 

[ronintexas]

My experience tells me it is either the PSU or MOBO...you are going to need to RMA one of them...to reduce downtime, it would be easier if you had a test PSU...I would recommend getting an RMA for the PSU first if you can't test a replacement....

 

[Wesdawg]

OK, so I pulled out the MOBO and the PSU, and set them on the table. The mobo is on, the CPU fan is spinning. I did this just after it wouldn't turn on in the case. So I'm gonna leave it on for awhile and see if it eventually turns itself off.

Keep in mind I did the same thing in the case with just the PSU and the CPU fan in the mobo after it turned off and it wouldn't turn on.

 

[Wesdawg]

Hmmm, OK, so just on the table with the PSU the MOBO w/o RAM eventually turned off. The fan stopped spinning. But, the MOBO's green light is still on, indicating it still has power. So I guess I've narrowed it down to the CPU or the PSU. I'm gonna see if I can find someone with another PSU that can power this MOBO.

 

[Wesdawg]

NEVERMIND. I figured out what was wrong. I'm so dumb. When running the PSU and mobo on the table I notcied the PSU fan wasn't spinning while the mobo was on. So I turned off the PSU, turned it back on, started th emobo and the PSU fan spins for a second and then stops. But the CPU fan on the MOBO is still spinning. Looks like I'm getting the PSU RMA'd.