This thing is so clogged that no air can flow through; the hot air ends up flowing into my case.
I always wondered why my 8800GTS ran at 72ºC: now I know why!
Unfortunately, this is the result of running my case with the side panel off. The sad thing is that, even before the dust, my computer will shut down with the panel on after like 10min of intense work. A new case is on its way; I just have to finish modding it!