Hi, I already have one gtx 660 (factory overclocked) and I'm thinking about getting another off ebay, they go for around $100 but I can probably get one for $75 if I bid. Im not worried about the extra power usage (I have a 650w gold rated psu) or the extra heat output. I've found benchmarks online for 660s in sli but the games they used are old and when I took for benchmarks for modern graphics cards they of couse use modern games for them so I cant tell how powerful 2 660s would be in comparison to a single new gpu. I dont really care about synthetic benchmarks because I doubt the sli scaling would be realistic to actual games. I know a single 660 is about as good as a 950. Also is this even a good idea? I dont really NEED to upgrade so I'd rather not spend over $100 or so on a new graphics card, I suppose I could sell my 660 and I'd have about $200 to spend on a new card but anything in that price range would be less powerful than 2 660s (I think?). I know theres a few threads already about 660 sli vs a single card but the solutions dont have any proof.