LOLOLOLOLOLLOLOLOLOLO
That's a fail mate, Is your fan even on during gaming?
The chip might be telling it to go slower on high load instead of faster(lolfail)
Your case looks shiz aswell :x
Confined space + high end gfx cards = nono
Try:
Click the fan tab, Set fan to 100%
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Get ATi Catalyst, Go to ATi Overdrive, Unlock the card, Set fan speed to manual 100% and if neccesarry lower clocks