Oh well, I don't mean to get OT but one thing that shouldn't overlooked IMHO is the performance/watt ratio(and even more so within an HTPC environment):
http://www.hardware.fr/articles/879-...nces-watt.html
This site doesn't allow pictures hotlinking so I can't provide a translated url, but the 650Ti delivers 67 fps/100W in Battlefield3 and the 660 only 54fps
I really can't wrap my head around tossing 180€ on a 660, especially when the 660SE is around the corner and that I don't care about games...so I'm pulling the trigger on a 90€ lightly used 1GB 650Ti
Buying used 5xx doesn't much sense as these are far less power efficient(34 fps/100W in B3 for the 560Ti
), second hand warranties aren't nearly as long anymore and their prices just aren't competitive(560Ti's regularly go for +100€ used).
Surely the 650Ti runs on a 128bit power controller but I'm quite sure it'll still be plenty fast in mVR anyway