Yes!
YEPP!!
Bootcamp is great for gaming. It runs windows better and is more stable than a PC!!!
Just remember to install the Bootcamp drivers and updates. It could also be a good idea to update the drivers of the card once XP (Vista is not as good for gaming) is installed with the BC drivers.
To do this:
1) Find and download the best driver for that card (For windows). DO NOT INSTALL!!!
2) Download and install Driver sweeper, but do not run it.
3) Go to control panel and uninstall the current ATI driver.
4) Restart windows
5) run driver sweeper and tick ATI display (or something like that), nothing else. Click clean.
6) Once all the bits (remains) have been cleaned, Restart again.
7) Install the driver
8) Restart and your good to go!!!