Question on SLI compatibility

Praedos

Honorable
Jun 2, 2013
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How's it going. I've been wanting to upgrade my ghetto rig & get a 660 ti sli going. That been said, my question is how related do the cards have to be to one another? And I mean specifically speaking, as my rig has a VGA msi 660ti PE 2GB Gtx, and the one I've been wanting to pair it up with is:

http://www.amazon.com/EVGA-GeForce-SUPERCLOCKED-Graphics-03G-P4-3663-KR/dp/B008S15X64/ref=sr_1_7?ie=UTF8&qid=1371092465&sr=8-7&keywords=gtx+660+ti

And if the two aren't compatible with one another, any suggestions? Price is irrelevant.

Thanks.
 

Praedos

Honorable
Jun 2, 2013
171
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10,690


And how badly would that affect performance? If it does at all? (Clueless in this field)