No it is enough. You have any idea how fast your processor heats up by turning your PC on? GPU's have always tended to read pretty hot even comparing to a processor.

Im pretty sure manufacturers will make some better solutions for the cooling. may that be as aftermarket or that come with em. personally I hope they do a 2-slot design again with the air venting out of the case.

No way 5 minutes of gaming is enough for any GPU/CPU to reach it's max temp, there's just too much "cumulative heat" effect. 20 minutes and I still would probably say it was too short, but at least it would be a lot closer to accurate.

Agreed mostly :) It is possible (quite cheaply) to have decent case cooling without the noise. I also draw air onto the cpu directly from outside the case to prevent any other overclocking affecting the cpu. After all, why not use the cpu fan to draw cold air in instead of it recirculating warm air. Another little trick is leave the pci slot blanking plate out next to the gfx card so cold air can either be drawn in over the gfx card or the hot air from it escape without affecting the case temps much. The airflow direction depends on the pressure gradient setup by your fans, but there will usually be air flow. check by holding a rizla near the case hole.