Random screen lock up

[Xiongmao]

Honestly, building your first computer is fun n all, until you get some random problem no one knows about/how to fix.

So I've currently had this computer for a little over a year, my parts are still under warranty. 

All cords are plugged in correctly. Nothing from the outside from what i can see isn't damaged.
Cooling seems fine, besides the first spike when turning on. Beep still happens turning on also.

My problem:
My computer is still on, but i lose all audio, mouse movement, and screen freezes. 
This can happen whenever, how ever long it wants too. This problem can happen over and over for 10 minutes after me force restarting. Or it can stop happening for six months until last week, and annoy me again.
Drivers as far as i know are updated. BUT-- This lock up can even happen on the log in screen to unlock desktop. Or on the windows flag seconds after turning on. Can happen opening chrome, idling on desktop with nothing on. I have even went to reformatting my whole computer and re-installing windows in case of a virus, or anything that was not installed correctly. Yes..Problem still exist.
--
My parts: 

- SAPPHIRE 100352-3L Radeon HD 7950
- Seagate Barracuda ST1000DM003 1TB 7200 RPM 64MB Ca - OEM
- CORSAIR CX500M 500W 
- Kingston HyperX Blu Black Series 8GB 

- Gigabyte 990FXA-UD3 AMD990FX ATX Motherboard

What i have tried: 
I have tried testing my ram sticks, putting in different slots, one at a time, both in different slots, etc. 
Also sent it off to a local computer store to be tested. He said cooling was fine also. Did a stress test over night, said nothing was bad and my computer looked fine, until he opened chrome and went to a youtube tab, and it froze. Hes willing to wipe my hard drive and see if anything happens, so Monday (today) ill be getting a phone call from him. I'll probably ask for it back if nothing changes. 

[Ohio]

Did you run anything when you cycled through RAM sticks? How about your computer guy? You might have a bad sector on one or more of those RAM sticks.

 

I have the same problem on my PC at home and haven't been able to pin it down either. However I have been pretty lazy with my testing (I've only ran a few memtests myself) as it only happens every other month or so. 

 

If you figure it out please shoot me a PM so I can test it on my PC, I'll do the same. 

[Xiongmao]

Did you run anything when you cycled through RAM sticks? How about your computer guy? You might have a bad sector on one or more of those RAM sticks.

 

I have the same problem on my PC at home and haven't been able to pin it down either. However I have been pretty lazy with my testing (I've only ran a few memtests myself) as it only happens every other month or so. 

 

If you figure it out please shoot me a PM so I can test it on my PC, I'll do the same. 

Yeah memtest programs and what not. Ram was ruled out as fine. The computer guy says he can manually test each part, but the sign says 65$/hr and ...yeah. An over night stress test to him would cost more than just shipping everything back and sky rocketing fees.

[TerrySuave]

Due to the intermittent nature, I would lean toward a voltage issue of some variety. I've used 3 of those motherboards personally without any issues in that department, but I'd still get into BIOS and shut off turbo boost and see what happens first.That, and verify your CPU voltages with AMD's recommendations. Gigabyte has a bad habit of cranking them up on many of their platforms. If that doesn't seem to do anything, I'd recommend trying a different PSU and seeing if the issue persists.

 

Edit: grammar

[mvitkun]

@Xiongmao Can you get ahold of another graphics card to try and run it for a few days to see whether the problem might be with the graphics card?

[Xiongmao]

Due to the intermittent nature, I would lean toward a voltage issue of some variety. I've used 3 of those motherboards personally without any issues in that department, but I'd still get into BIOS and shut off turbo boost and see what happens first.That, and verify your CPU voltages with AMD's recommendations. Gigabyte has a bad habit of cranking them up on many of their platforms. If that doesn't seem to do anything, I'd recommend trying a different PSU and seeing if the issue persists.

 

Edit: grammar

Got my computer back today. You're spot on with the problem He believes it's the motherboard, or could be the powersupply. He awkwardly didnt have a spare of either of those, and tested the other two parts. Thankfully my problem is that annoying he didn't have to test each part over night. He told me since i'm still under warranty i should just send back in the motherboard. But i'll prob look into your advice first. 

 

@Xiongmao Can you get ahold of another graphics card to try and run it for a few days to see whether the problem might be with the graphics card?

Computer store guy said graphics card is healthy and fine. 

[Ohio]

I hadn't even checked voltages on my machine yet, I'll look into that when I get home!

 

As far as PSU's go, if it happens to be the same issue I was having, I know I've swapped my PSU a couple months ago for an HX1000i and have still seen the issue (albeit not nearly as frequent, so if it is a voltage thing it might be lessened by a more stable power supply).