Graphic Card runs slower when overclocked?

[lorenzomista]

Hey guys! I'm new to these forums and I had a question. My Graphic card is getting funny results while using PassMark PerformanceTest 7 trail edition. I seem to get a higher benchmark with my card running stock, then I do while its overclocked. I overclocked it using Catalyst Control Center. Here are my results for the 3D tests:

These tests are set to be very long, instead of the default setting.

ATI Radeon HD 5830 stock(GPU @ 800 and RAM @ 1000):
First test: 2001
Second Test: 1992

ATI Radeon HD 5830 OC(GPU @ 900 and RAM @ 1200):
First Test: 1980
Second Test: 1976

I ran the tests twice! Does this mean that there is a glitch, or did I overclock the card wrong? I'm not sure what's going on. I asked for help on Overclockersclub.com but they didn't know what the problem is and told me to come here.

My specs:
AMD Athlon II X4 640 @ 3.6 GHz
Cooler Master Hyper 212+
Biostar TA785G3HD
Western Digital 320 GB & Samsung 2TB
Rendition 2 GB DDR3 1333 8-8-8-24
CoolerMaster GX 750W PSU
XFX Radeon HD 5830

[David (PassMark)]

The results are very very close. About 1% apart. As the results are so close, you should run many more samples to determine if the difference is noise or a real difference in performance. (It is normal that you get a few % of difference between runs, due to background tasks that are always running in Windows).

My guess would be that you are more CPU bound than GPU bound. That is to say you need to improve the CPU performance before the O/C on the GPU is noticeable. By the same taken you'll probably find changing the clock speed on the CPU moves the test results more than overclocking the GPU.