I'm running Source games at their highest quality and native resolution and it rarely ever dips below 60fps, if at all.
http://steamcommunity.com/id/tsol/screenshots < some of my screenshots taken with this card. I'm still just using the bundled Apple drivers for now. I figured I'll get the better ones when I start to notice modern games running bad. But for now the stock ones will do!
I haven't had a AMD/Ati laptop for awhile, but for Nvidia I have always used modded desktop drivers for my laptop.
Nvidia had a policy where the manufacturer had the responsibility in updating their drivers and bootcamp drivers have always been a few generations behind