Your cpu doesn't have much bearing on if you can run that gpu. What does is your motherboard. AMD gpus are backwards compatible upto a point. You can use pcie3 on a pcie2.2 or later board. Prior versions used a different power architecture, so are unlikely to be compatible. For instance, if your motherboard is pcie 2.0, it may not work, if your motherboard is pcie 2.2 it should. If your motherboard is 2.0, youll probably have to search for an older generation gpu which would be compatible.
Nvidia gpus are fully backwards compatible from 3.0 to 1.1, so that may be an option, with your psu I'd suggest the gtx 750.