Unable to choose a graphics card for my new build

[stevenk92]

I have a few questions regarding GPU's. Do the memory interface matter when looking for a graphics card?
I am debating between a asus 660 ti and the sapphire 7950.

 

[Firedrops]

What. Why is there a debate at all, unless money is a concern? The 7950 is of a much higher tier than the 660.