Hi! I have an iMac on order, but I can't stop wondering if I should instead buy a dedicated gaming PC and a thunderbolt display. It's important to game in native resolution for best graphics clarity, but some games are very demanding at high settings even for the 2012 iMac 27''. I've heard about something called "centered" mode, which means that when you choose a lower resolution than native in Windows 7 for better gaming performance, say 1080p, the active image will retain the same ppi/pixel density - but use a lesser part of the screen (with a black frame around the active part of the display). Is this possible (nvidia drivers?)? That would make a huge difference for me, to turn down the resolution and still get the "native" visual clarity. I've tried to google the term, but I can't find anything specific. Anyone? Thanks!