It will not affect much of the Performance.
According to this: http://www.tomshardware.com/reviews/cpu-performance-comparison,3370-16.html
The card used there is 7870 which is as good as GTX 660
EDIT: Scroll down and find Crysis 2 & Mafia 2. Its not good as i5. But will get the work done.
Upgrade in future if you can