random shut offs

Hi guys. Having some issues with my new build. First here's my specs:

Windows 7 Home Premium 64bit
AsRock Z68-Pro3 Motherboard
Intel i5-2500K CPU
G.Skill Ripjaws X 1066MHz 8GB RAM
2TB WD SATA3 HDD
1TB Hitachi SATA2 HDD
60GB OCZ-Vertex2 SSD
180GB WD SATA HDD (from my old computer - got stuff on it I didn't want to lose and putting it in the new build was quicker than waiting for files to transfer)
Gigabyte 1GB HD6850oc duel fan
Gigabyte Odin 720W PSU
Coolermaster Hyper 212Plus CPU cooler


OK, so the problem I'm having is random power outages. It's not an external issue, (we don't lose power to anything else in the house so I'm sure of that. But every so often my PC will just flick off and reboot as if someone has hit the switch at the wall and turned it back on. It's different to the way a computer turns off when hitting the reset button. You here the power drain out of everything and it's about a 5-10 second delay before the PC reboots. This happens quite randomly. The PC will run fine for a week, performing all the duties I require it to -internet browsing, word processing, watching movies, listening to music, streaming media to my lounge room, playing games such as Battlefield BC2 and Left 4 Dead 2 etc. It does all this with no issues then suddenly, usually while chatting to a friend via Facebook or something it'll flick off and then it'll do it 3-6 more times (depending on it's mood) before settling down again for another few days. After rebooting each time it'll be good for a few minutes before losing power again.

So first I thought I might be experiencing some issues with the connectors, so I powered down, removed, cleaned and reset all the power connections. Didn't work.

I thought maybe it was an over heating issue so I downloaded Core Temp and noticed something interesting - The CPU usually sits around the 25 degrees Celsius mark consistently across all four cores but randomly and only once after start up Core #1 and core #3 will spike up top 98 degrees! I have set up Core temp to give me warnings for overheating which is how I discovered this. I have also set it to create a log so I can check it next time my PC plays up like this. Going by the averages though I feel safe counting that out as the culprit.

Lastly, my thoughts travel to the PSU. It's brand new out of the box and has plenty of juice but I do have quite a few pieces of hardware running off it. Perhaps too much. I am now going to take the time to transfer everything from my 180GB HDD to my 2TB HDD so I can then ditch that drive to save energy but I'm worried that might not be enough weight trimmed off from the power consumption to make a difference.

Can anyone offer some advice about this please?

 

The CPU temp spikes really concern me as there's no way they should ever go up that high with a Hyper 212+(I have one on my 2600K rig). My 2600 is highly OC'd and always @ %100 load 24/7 and hardly ever goes over 70C, depending on ambient temps of course.

I would do a torture test with my favourite burning in app., OCCT(there's also a beta if you wish) which loads up every subsystem to the max and the key feature here is it records graphs to the HDD until the machine craps out. I would at least re-install the HS/F cleaning the old compound off and reapplying then retesting.

I doubt it's the PSU as I'm running my 930 the same way as the 2600 plus the video cards and your 6850 takes the same power as my 460 alone. I didn't know gigabyte sold PSU's, probably re-branded, both my rigs are powered by Corsair TX750's.