PC reboots after hours of heavy load.

[PrimoJones]

Hello everyone!
I seem to be having a problem with my system lately...
Here are my specs
MB: Asus M4A79 Deluxe
CPU: Athlon II X2 555 Black Edition
RAM: 2x2GB Corsair 1066 @ 800
HDD: Hitachi 500GB / Seagate Green 1500GB
GPU: 2xHD 5770 1GB
PSU: Corsair HX750W (Silver rated)
OS: Win 7 Ultimate x64

The CPU is unlocked and was overclocked.

I have no problems with daily use but when I decide to encode a video after a few hours it restarts. I was running overclocked so I restored it back to the default speed and the restarts stopped for a while and it managed to do over 20 hours of prime 95 without a problem. Yesterday I set it up for encode and when I got up i noticed that it had restarted itself. In the usual case most people would suggest its the PSU - but this time I'm sure it can handle it, temperatures are at 50C at full load, when I play graphic intensive games I have no problem with restarts (so excluding the video cards as well), ran memtest for a few hours without a problem, my HDD's have like 10 GB each free speace.

Can anyone think of a solution? - thanks in advance.

 

[MT Alex]

I used to get random restarts using Catalyst 10.12, which had to do with the computer entering or exiting sleep mode. This maybe the case with you, since it happens during tasks that take an inordinate amout of time. Just a guess, since I see you are using 5770s.

 

[PrimoJones]

I used to get random restarts using Catalyst 10.12, which had to do with the computer entering or exiting sleep mode. This maybe the case with you, since it happens during tasks that take an inordinate amout of time. Just a guess, since I see you are using 5770s.

Come to think of it I did setup monitor turn off after 20minutes not so long ago.
Using Catalyst 11.3 at the moment. Hmm.

 

[MT Alex]

I'm not sure, my sleep restarts were cured when I ditched 10.12. Never used 11.3, though, skipped from 11.2 straight to 11.4 preview. Sounds like it must be something else.