The 560ti, as drums101 has said, is noticeably faster, here is a benchmark comparing the two: http://www.anandtech.com/bench/Product/536?vs=547#
Now, if you wanted to compare the 7850 vs. 560ti, then the 7850 would be the better card. Or even the 7870 since it's around the same price range of most 560ti's.
http://www.anandtech.com/bench/Product/549?vs=547#
http://www.anandtech.com/bench/Product/548?vs=547#
Why are you asking for a comparison of two cards that are in two completely different price brackets?