I think u could get more fps out of ur card. If it were my computer I would have it more with that spec computer.
I had my card since it came out, and is still better than some of the faster ones.
Why u maybe asking well I tell you y.
My computer is balanced. Which means that nothing is trying to take more power out of something else.
What happends is that if your memory needs more than the graphics card can cope your computer might lagg or be slow starting up because there is alot of strain on the graphics card.
Your computer only runs as fast as the slowest component in ur system.