I just love how at the very slight mentioneaning of gaming everyone just goes: " Uooo dude, get the 680MX. Futureproof that mofo, it's only like 2500$. Small price to pay to play Starcraft2 or Angry Birds, right?" Well no, if you want to be ignorant about it and pay that amount of money in order to have some sort of future proofing(i just love this term) to be able to play "casual games" in 2 years....you better buy the High End 21.5" and change it annually and you'd still come cheaper and have the latest and greatest. The GT650M is a capable card, it will run the games u mentioned and some just fine. Don't listen to those who automatically push you to the 680MX as soon as they detect "gaming" in your post. But hey, it's your hard earned money!
I have been pondering this issue for quite some time since I ordered the 27" with the 680MX, and i7 processor. It seems to me like I would've been better off ordering the high-end 21.5" because I too will be using the iMac for general purposes, with gaming being an added benefit. I really have no real uses for the real estate of the 27" or an i7 processor; my purchase was made purely on the premise of "future-proofing," where in retrospect, is quite silly because technology evolves at such a rapid pace, it's almost futile to try and keep up with. I'm still not fully convinced about my purchase, and may just end up going for the high-end 21.5" with a 1TB Fusion drive (I can see how that will be of practical use and benefit to my workflow and enhance my experience), an i5 (plenty powerful and don't need hyper threading), and 16GB of RAM. In addition, the 27" just dwarfs my workstation, and will end up detracting from my experience because it will take up a lot of space and I will have to end up sitting too close to it. I think the GT 650M is a capable card and will suit my needs just fine (Youtube videos of "GT 650M" demonstrate it is quite capable of handling a lot of modern games i.e., Assassin's Creed 3, Hitman Absolution, Far Cry 3, at high settings with respectable performance). As someone switching over from console gaming, I'm sure it will be a definite improvement over what I'm used to. I do however believe that if you're a gaming enthusiast and need to game at native resolution with a 100 FPS, then by all means, get the 680MX. I really wish the 27" was in stores in order to make an accurate comparison.
----------
I find in these threads the terms ultra, high, med, and low are used in describing game settings. My only experience has been gaming on the 360 and PS3. What I want to know is what PC game settings would be roughly the equivalent graphically and performance of a console. I am looking at a refurb 21.5 and trying to decide between the baseline 6570 GPU or having to go over budget to the 6770.
I believe most console titles are programmed at low-medium settings and capped at 30 FPS with a 720P resolution. PC gaming most undoubtedly trumps console gaming. I would dare to say even the GT 640M can display better graphics than it's console counterparts.