The R7 260X would be your best bet in most games but not in CPU heavy games like Battlefield 4, Crysis 3. I almost get a 90% CPU usage on my old rig's Phenom II X4 965 BE. But this card will definitely complement your old CPU. Even the old HD 7770 will be a very good and complementing GPU for your system. Welcome to PC gaming. PS4 and XBOX One can never give a PC gamer the joy that a PC can.