Hi,
This may help to improve your FPS.
Install the game you want. then uninstall all the games/Programs that you no longer use. Most ppl keep PC's like a mini program junkyard ;). 'One day i will play fifa 95 again' kind of thing.
Once that is done get yourself a registry cleaner personally i use Auslogics (free trial with it so if it don't work don't buy it) but there a re loads out there. Then a disk cleanup (CCleaner will do) and finally run disk defragmenter.
I have done this at home and in businesses many times and seen both FPS and perfromance increase massively.
Also make sure that no other programs are running int he background stealing your RAM and CPU use. If your not online then deactivate the Anti-virus software. BUT remember to switch it on again before connecting again.