Hi Guys, well I'm gonna make an Upgrate for my GPU (GT 430) but I don't know what GPU buy.

Betwen GTX 750 Ti or R9 280x

What do you guys think about it?..

(I don't really care about the graphics, but I care about the FPS)

My PC:
AMD FX 6300 3.9 Ghz
8 GB RAM 1600Mhz
GeForce Gt 430
Gigabyte GA-78LMT-USB3