I recently switched cases and since my new one has no intake and a ton of exhaust my air pressure is very negative inside the case. Thus, my ATI silencer which never moved much air anyway now can move hardly any at all. I have my X800XT overclocked to PE without any sort of mods and before it ran at 55C fine, now it runs at 63-5C but gets artifacts mostly in 3Dmark but sometimes in games too. What's up? I mean... it's hotter but the stock fan doesn't even speed up until 72C so this is well within the acceptable range. Also if I take the case shell off the artifacts go away (and the GPU drops about 8C).