Dolphin, the GameCube and Wii emulator - Forums

The 750 and 750 Ti normally just run off PCIe power. If OP's only limitation is the number of lines from his PSU, then he can go better than that. although my GTX 770 is 6+8, there are definitely 6+6 ones available.

Again, though, I don't know AMD anymore, since they changed their naming scheme.