your cpu may hold gaming back and bottleneck those mentioned cards because q6600 lacks hyperthreading necessary for almost every latest game.....but still as brett said, every game on high to very high but not ultra......
btw what resolutio do you play at????
Games do not need hyperthreading the i5 3570K is the best CPU for gaming thats not silly money and it also lacks hyperthreading. But you are correct his CPU is a bit dated for a high end card but not much.