I'm monitoring the GPU and CPU temps using RealTemp, and even a game that's not too graphics-intensive like WoW can push it to 75 degrees C. Running DotA 2 gets me up to 80, and if I accidentally leave both on at the same time, it hits 85 and the fps starts slowing down noticeably. Is this normal behaviour? Do I need to buy an external cooling fan?
that series video cards got really hot.... ( not that they all don't ).... however, if the card has been in use for a while it might be time to pull it and blow the dust and lint off the heat sink. ( blow hard through the exhaust port so the air goes through the fan in the opposite direction to which it normally blows. If that doesn't help try reapplying thermal paste.
I assume you are using the stock model (reference card) it is a bit higher than most cards i have seen, but it is still within a more or less safe range. Running a stress test these cards heat up to about 77-80+C, however while gaming it should be lower, so yours is a bit hot. I believe it is still within range, keep the temps under 90C, however your temps should be lower. Most cards of the gtx500 series I have seen run a bit cooler, but fermi cards (gtx 400's, 500's) are known to run a bit hot.
How is your case cooling? Is your case large? How many fans?
Is your GPU overclocked? Is your fan set on AUTO, try upping the fan speeds in manual mode, but be careful not to accidently turn off the fan or set a low fan speed.
Intel Core i5 2500K oveclocked to 4.5 GHz with a Coolermaster Hyper 212 Plus fan
ASUS P8Z68-V/GEN3 motherboard
Corsair XMS3 Dominator 2x4GB RAM
Geforce GTX 570 GPU
Coolermaster CM 690 II Basic case
Built this computer about 2-2.5 months ago. The area it's in is not amazingly ventilated, but it's not terrible either (it's got at least a foot of room on each side). The CPU has no temperature problems, never seen it go above 60 except for when I ran those tests after I OC'd it. I'm guessing it's just that the case fan is weak and I need a dedicated GPU fan.
you have spaces for 2 fans on the side panel. are those empty or did you put fans there? You should take your side panel off and check your temps at load again. if the temps come down, your gpu is not getting enough air and you should add these fans. If they do not come down, there might be another problem.
No, the case is only cooled by the stock fan in the back.
Just tried it with the sides open - still hit as high as 77 just running WoW with no other programs open. I feel like this is worse than it used to be (I actually noticed some fps drop for virtually the first time), so maybe the issue is dust?
I just opened it up and blew a bunch of dust out of my GPU. I'll test it more over the course of the day, but it seems to have gotten a little bit better - seeing temperatures lowered by 5-10 degrees. Might need to put another fan on the side if it keeps being an issue.
I'm not picking on you but I have to laugh about how "politically correct" these things are.
I blow through them with my mouth and use cotton swabs where applicable.
Heh, reminds me when a buddy of mine who's experienced with building computers came by to help me build this one. I asked him "wait, don't we need a pair of those grounding bracelets?" and he just shrugged, touched the metal leg of a chair and said "good enough".