That's against a single 560ti. (Of course a single 560ti loses)
This is more in line with the OP's question: (GTX 560 Ti 2Win is two 560ti's on a single card, in SLI)http://www.legitreviews.com/article/1805/5/http://www.legitreviews.com/article/1805/11/
Now if the price is close, the single card is probably the safe bet.
However 560ti, in SLI actually does a little better than the single 7970 in these tests.