Not too bad. I had to lower the settings to medium to get a smooth frame rate. Not sure how to tell exactly what the FR is, but its smooth to the eyes so not a big deal. And it still looks excellent. Great graphics. And as expected the fans are on full blast the entire time playing. Im using an external mouse and kb because its very hard playing on the mac mouse/kb. Over all its not bad. Not as good as I expected, but usable all day like this. Next I will be playing Civ 5 and the Simcity games. Those should run full detail without issue. What other games are great on the rMBP?