Also a little thing I was not aware of before recently too, as I use both gpu and cpu.
I never noticed it before, but if I have the cpu going on all 4 cores, it kills the gpu. I thought they’d have been separate, but then I read about it and it seems I need at least 1 core to keep the gpu kicking.
Bugger. but it makes sense.
So I’d kick off cgminer and minerd and occasionally I’d see cgminer crawling at about 20-100 and could not work out why. Only recently when I stopped using a frontend to start them both on selected pools, did I realise it was the issue, and I noticed that without cpumining I was getting a lot closer to 400khash/s than the 380 I was used to seeing. I don’t know if it was due to not using a priority setting when starting minerd or not, but it’s not worth me mining both on the same rig.
Just something to think if the OP’s issue doesnt resolve and they do run something that grabs the gpu or interferes with it running at full.