oc reduces performance

[ljsimpson]

I overclocked my sapphire radeon hd 7950 and then ran furmark. I didnt notice any artifacts, but when i compared the average fps count to that of the unoverclocked card, i found that the gpu actually performed better unoverclocked. I reran the test a few times to make sure. i tried 1200/1400, 1000/1300, and a few other core clock and memory clock speeds, but got similar results. Anybody know why?

 

[3DVagabond]

You could be running into;

Thermal throttling
power limits
memory latency at higher clocks.

Increase fan speed, up the power slider to the max, and O/C the GPU 1st and then O/C the mem to see if you get more or less performance.