AA (anti-aliasing) is used to make lines appear sharper. IR (internal resolution) is used to increase the resolution of all the in-game textures and features.
Try putting your Fullscreen resolution to Auto, and putting the IR to 1x and the AA to none. If you're still getting a lag, then it isn't a problem with your graphics card, but either your CPU or textures.
Try putting your Fullscreen resolution to Auto, and putting the IR to 1x and the AA to none. If you're still getting a lag, then it isn't a problem with your graphics card, but either your CPU or textures.