Which graphics card should I buy for this rig?

[Domfoz]

Hello. I am going to buy a new PC for gaming this september, from a budget of 450$:
Asrock FM2A55M-DGS
AMD Athlon II X4 750K
Arctic Freezer Xtreme Rev 2
Kingmax 4GB DDR3 1333MHz
Sharkoon VS3-S Case
Chieftec CTG-500-80PB PSU
I found the HD 7770 and the 7790, but I can't choose between them.If I'd have to buy the 7790, then I would have to sacrifice the cooler, and I am curious about i my CPU be bottlenecked.But with the 7770 I'd have a good cooler with the PC. ( I have a relatively low-res monitor (1360x768). )

What do you think?

 

[fountainpen]

with a hd 7790 you will get much higher FPS, if you don´t overclock i would take a hd 7790, if you will overclock you probably need a aftermarket cooler because with my experience with amd they will run very hot and loud.
if you will overclock i´d still reccomend the hd 7790 and safe some money for a cooler.
and i don´t think a X4 750K would bottleneck a hd 7790