Artifacts after CPU overclock

[Cragzman]

Hallo fellow geeks.

While messing about with overclocking and benching (still a tad noobie), just for a laugh I ran Unigine Heaven 4 on on a loop with the following:

Phenom II 965 @ stock 1.325v LLC High (with an H100i)
HD7950 @ stock
GA-990FXA-UD3
Kingston Hyper-X 8GB DDR3 @ 1600MHz
CM Silent pro Gold 1200W (overkill I know)

With this, its runs as expected with no problems at all. But if i OC the CPU to... lets say 3.8GHz @ 1.350v LLC High, run Unigine Heaven 4 again on loop, after some time, the screen goes black, and the FPS counter in the top right corner reaches 200FPS+ and top menu remains.

Here is the best bit. When this happens, I envoke a force close of Heaven and then artifacts happen. Like if I open up IE10 or Firefox, some of the text within the window either has huge gaps or the text is absolutly huge. It changes when I scroll. A reboot of the machine seems to sort it.

What would be the first thing you would check? All the temps seem grand. CPU not going over 42c, and GPU operating well within safe limits.

Any ideas?

Cheers

 

[Cragzman]

Just to update, I have been browsing through various Google results reguarding my CPU overclock causing graphical artifacts. I have come across one avenue that I haven't investigated yet. It is to check if my PCIe frequency is on auto. People are suggesting that it may need to be manually locked at 100MHz or something.

I shall try this when I get home later and report my findings.

Cheers ears

 

[Cragzman]

Doh! After further mucking about, I made the dumb schoolboy error of not setting the LLC to the correct setting and adding more voltage (feeling like a dumb arse). After setting the CPU voltage to 1.375v, and changing the LLC from High to Ultra High, the voltage stays steady at 1.390v at idle and full load. Ran OCCT for few hours and Unigine Heaven for few hours with settings at full whack with no issues.

Just kinda getting my brain around the LLC settings for AMD CPUs. Looked so easy on TTLs guide to overclocking. But I think I have got there in the end. Now to see if I can step up towards 4GHz+ and bugger aboot with the NB side of things.

Woop!

 

[Jeff_s510]

interesting....ive never seen that kind of cpu issue before

 

[Cragzman]

Neither have I. Been scratching my head over it for a while. At least with the new settings, it seems happy as Larry. Whoever he is.