I have an early 2009 iMac base model with the 9400M integrated graphics. Trying to play Team Fortress 2 at native resolution on the 21.5" mac but its really struggling. Am looking at upgrading this mac to the better spec 21.5 model (1Tb etc) currently out or the 2012 model when it arrives. Will the new one play TF2 easily or will i have to buy the 27" 1Gb GPU version? On a completely different issue I have noticed dark marks all along the top of the screen when it rebooted the other day (first time I have rebooted / turned it off in 6 months). Thought it was dirt on the glass but it wont come off. Applecare is still in place, should I contact them to see if its something that can be fixed?