GTX 660 SLI or 1 GTX 660Ti

[shaunw50]

So I am going to get either

2 MSI GTX 660 and put them in SLI

or

1 MSI GTX 660Ti

I do have the powers supply for it, 750watts.

So which is better or is there a better option on the ATI side which performs better than both of these cards.

Also I don't want to pay for a GTX 670 when I could overclock GTX 660Ti and get it to GTX 670 performance.

 

[shaunw50]

I looked at the AMD 7950 which I think is same graphic card to nvidia side as GTX 660ti... 7950 offers 4 games at the moment?