I have an i5-2400, 8gb ddr3 1600mhz ram, hd 7850 gpu, 750W 80+ bronze xfx psu. looking to upgrade my gpu. what do you guys think would be an optimal pairing with no bottleneck and the ability to play with high to max settings playing mainly world of warcraft, Black ops 3, elder scrolls, gta V. thanks for the advice in advance.