Low FPS in StarCraft II

Ever since I set up my computer and installed the ATI Catalyst drivers, I never bothered to uncheck the box for Adaptive Anti-Aliasing, assuming it was a feature only turned on if regular Anti-Aliasing was in use. As it turns, out, it's not.

As I returned from my holiday and got to install StarCraft II on my own computer, I played a few games versus the A.I to get used to the game. One of the games I played was on the map called Twilight Fortress versus three computer A.Is, and I started out with an FPS of 20-25 (in-game FPS-counter is displayed by pressing Ctrl + Alt + F) and found that to be far too low as opposed to what my machine should be able to do, and not consistent with the experience I had on other maps.

I started to fiddle with the in-game settings and eventually found a working setup, but I couldn't get over the feeling of having a crippled computer, so I went into the Catalyst Control Center and checked out every setting under the 3D tab. When I got to the Adaptive Anti-Aliasing and disabled that, everything went alot smoother.