660ti running better then mac gtx 680

I was playing Starcraft HOTS with my friend last night and found that his 660ti was performing as well as my Mac GTX 680, if not slightly better.

He has a
2009 pro with a 120GB mercury accelsior, 8gb 1066 ram, 660ti, 3.2ghz quad w3570. Then a 30" dvi 2560x1600 monitor.
I have a
2010 pro with a 120GB mercury accelsior, 12gb 1333 ram, mac gtx 680, 3.2ghz quad w3570 running on a 27" apple cinema display (2560x1400).

Were both on the latest version of the 10.8 and both were running max settings and resolutions.

Any ideas why the 660 is performing like my 680?

**** update on 8/16/13
So after some more testing. The day before he did not have AA turned on. Once enabled I was about 20 Frames better. Also I think the graphic cards ability to do Vsync automatically was going into play. Shortly after playing I noticed it was not going over 60fps. His was staying at about 65 so I dont think vsync was happening on his.

ActionableMango said:

Is one of you using newer web drivers?

Maybe it's just SC2. Have you tried GPU benches such as Heaven and Valley?

Click to expand...

I was using the newer web drivers.
I dont have either of those to test with.

At work we were talking and we believe that it may be due to him not having AA enabled, where as I did. Were going to be doing more "testing" tonight.