IMHO, (since i'm a cheapskate), save the 10 dollars and frustration of trading in. The difficulty in accurately suggesting one over the other is that dual GPU's tend to be compatible and incompatible with different things. Where an SLI setup might be really good, a CrossFire could not, and vice-versa. Honestly, you won't see much improvement over a single GPU at the price range and cards you are talking about (don't believe otherwise, you could just be wasting money). Again, this is my opinion. I'm running a single GTX 460 768MB at 1920 x 1080, and almost every game gets 60 fps at very high...maybe not always ultra...examples include CIV 5, Sniper Elite V2, Battlefield 3, Borderlands 2, Skyrim, Brotherhood...etc. Yours will blow mine out of the water, performance wise, but you won't see a difference since games have fps caps at around 60...the question you are asking is reliant upon whether you would risk compatibility with CrossFire or SLI. Also, whether your mobo can support them.