Strange BSOD problem?

[TheEskimo]

I need some BSOD help here, guys
System Specs:
i5-2500k, stock speeds and fan
Sapphire 6870
WDBlack 500gb
Asus CD/DVD burner/reader
Antec 300
Gigabyte P67A-UD5 B3
Windows 7 64bit, OEM
Corsair 650W
8gb g.skill Ripjaws DDR3 1333 (PC 10666)
It's a new build from this Thursday.
Here's the problem. I've used it for 10 hour gaeman and work sessions, and it works great, in fact stupendous. However, I get BSODs ONLY when I leave the computer alone. I'll leave it unattended, with programs running, for perhaps 30 mins, and then it gets a BSOD, saying that there was an uncorrectable hardware error. All my drivers are up to date. The only problem I could seee is that both onboard sound, and the video card sound are both enabled. Could these be conflicting?
The only other thing I could think of is perhaps the memory is bad? I have not run any memory tests, but I assumed that it is fine.

 

[ridinon0$]

Is it happening when the computer goes to standby or hibernate? Try changing the setting to 1 hour and see if you still have issues in 30 minutes.
http://www.google.com/search?q=bsod+hibernate&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a#hl=en&safe=off&client=firefox-a&hs=Qbq&rls=org.mozilla:en-USfficial&sa=X&ei=v_nGTZrNNoWctwfy2LWjBA&ved=0CBUQBSgA&q=bsod+hibernate+win7&spell=1&bav=on.2,or.r_gc.r_pw.&fp=44b3839bd44fe786