When people say optimal experience that's 50-60fps Medium- High. I have no clue how you can take playing a pc at a frame-rate of 30-40. I have never understood why console games play fine at 30s while if you try a pc it just feels awful...maybe its because of the mouse.
Trust me get a better a card and you certainly will not regret it, I certainly didn't. That graphics card old and new games are optimized for new hardware not old.