I have a slightly newer macbook that a friend (his was the last of the older design), and I'm not a technical wizard but he had less RAM than me which I assume could affect the speed of running games? But anyway, Playing games like Team Fortress 2, my mac lags every other second, at first I thought it was my internet connection, however even playing offline games like Minecraft and some other offline games downloaded from the app store, the game works fine for a few minutes then the speed slows down then reutrns to normal and repeats literally every two second, like it's lagging. I have no idea why it does this when an older macbook that my friend has can work perfectly fine. He recently upgraded his ram to the same as mine and is happily playing Diablo 3 when I can't even play Minecraft or Team Fortress 2. Any help anyone???