I'm considering buying a new iMac and am wondering what the GTX675MX will do (have a hard time finding comparisons or tests with that). I plan to use it for gaming (part with bootcamp/Windows7 if games not available for MacOS)
I think it's a mobile card and with the space restrictions it can't have the same power as (lets say) a PC GTX 670, so next to which PC GTX cards does it fall (I have a GTX 560 in PC for example which now tends to move towards falling down the cliff on the weak side).
It's just theoretical, but according to the PassMark test, the 675MX should be about 30% faster than a desktop 560. This is on the PC of course and some system specific may flow into the comparison, but at least there is a good chance that performance is at least a bit bettter than your GTX-560.
DO NOT GET the imac 680mx!!!! save and get 675mx same performance but with less cudas 1344 and 1 less gig of vram. Still running battfield 3 ultra 43fps 1440p check this site http://forums.macrumors.com/showthread.php?t=1568279.
