I just bought my first Mac computer but I'm baffled at this mysterious behavior. I hope someone could try this out on their Macbooks for more statistics. Everything seems to be in order in my Macbook Air, but whenever I play a game fullscreen, the CPU temps rise to 80C and the fans slowly follow until they're running full speed. But the catch is, these games are NOT this intensive. They all run fine windowed. For instance, I was benchmarking Minecraft like this and found that it runs on a steady 70C with no action on fans. But when I switch it to fullscreen, everything goes maximum in a heartbeat. I can see no visible difference in the game graphically or gameplay-wise. What's more, if I switch the game to fullscreen from the green button in the window borders left-hand corner (like I would Safari etc.), I will be able to bring the system bar down by pointing the mouse at the top of the screen. But when I do this, the temperatures again start to drop dramatically, like I was playing on windowed. The games I've tried this way remain perfectly playable and again, no visible lag or downscaling whatsoever takes place. What is this?! Faulty internals? Odd CPU priority management? Bad OS programming? I still have two weeks left to return it to the store and I'd want to get to the bottom of this. It's kind of becoming a deal breaker. Cheers all.