What's a safe oc for an eVGA 6800nu if I am using the stock cooling. I have 6 case fans and there are 2 spaces between the vid card and the next pci card...one of the case fans blows right on top of the card. I'm not sure how to accurately check the temps for video cards, so if somebody could point me to something that can do this and also tell me safe temps for this card? Thanks.