GTX 660 vs 670

Hardware GPU
1

So I've been working on my first personal rig, still in the concept phase, but I am starting to narrow down my parts list. 

http://pcpartpicker.com/p/HbM6

I was looking at the MSI GTX 670 PE, but as I was browsing arround I found this Asus GTX 660 

http://www.newegg.com/Product/Product.aspx?Item=N82E16814121660&cm_mmc%20=AFC-dealnews-_-NA-_-NA-_-14-121-660

I know that there is a significant performance difference, but what would the fps difference be between the two cards? I am looking at bf3, skyrim, and minecraft. Not looking for max graphics. What do y'all recomend?

EDIT: I realize this is a bit of a vague question, but I am very new to the computer building world, so I am not sure what information I really need to be looking for.

2

I'd say 660 Ti. I'm not sure where it stacks up against the 670 but I can play almost anything at max with 40-120 fps depending on the game.

Minecraft runs at about 105 normally, as a reference.

 

Full Specs:
Mobo: Asus M5A97 LE R2
CPU: AMD 8350 (stock clock, stock cooler)
RAM: Corsair 1866 MHz 16GB
PSU: Corsair TX750M
HDD: SanDisc 256GB solid state, Western Digital 1GB 7,200 RPM
GPU: Asus NVidia GTX 660 Ti 2GB (stock settings, automatic boost with GPU Tweak)

3

670, why get a POS like the 660Ti?

 

Crippled bus width is crippled...

4

The more I've been looking arround it looks like I am leaning more towards the 670. I'll look arround for some 660ti's but many models that I have seen are discontinued.