670 overclocking stability?

So today I overclocked my 670 power edition to 1319 mhz core 3505 mhz memory, ran about 10 different tests in kombustor to find my (near) max overclock (+140 at the moment, it started crashing at 150) I have my voltage on 1.175 and my power usage at max (114% maximum) after about 40 minutes of stress testing at 1920 x 1080 In kmbustor my card seemed perfectly stable (for the entire 40 minutes it was running maxxed out at 1319 mhz and 3505 mhz). I then decided to test on unigiene heaven 4.0 (at ultra settings, 1920 x 1080) and I found it would blackscreen for a few seconds, then come back at around 5-6 fps until I tweaked my overclock.

Is there a way to fix this?
Am I doing something wrong?
Why didnt it do this for the 40 minutes stress test plus the 10(ish) tests I put it through before that?

Thanks for any answers!  

Well it does sound like there may be a Problem with you OC, but try playing a game or running Unigene Valley, Heave gave me so many problems when trying to OC my 7950, but Games and every other benchmark worked flawlessly.

Ill go try metro 2033 for a few minutes then ill post my results. Thanks for the reply


does it in metro aswell, except metro full on crashed rather than with frame lag. Lowered my gpu clock by 10mhz, ill do some extra testing when I have time