Nvidia GTX 770

Hi im in the market for a new graphics card and I have chosen the Nvidia Gtx 770 as the best performing card for my price range but I need some help choosing between the various different brands of 770 my computer specs are as follows;


8Gb RAM
AMD FX4170 quad core processor 4.2Ghz
Nvidia GT630 Graphics card (Currently)


I have narrowed it down to these two options;


Asus GTX 770 Nvidia GeForce DirectCU II OC 2GB
or the
EVGA Nvidia GeForce GTX 770 Superclocked 2GB


Both are around the same price (on Amazon) but which is better in terms of performance or is there no real difference, any help would be greatly appreciated
Thanks!