Anti-aliasing uses up video RAM like crazy and requires more processing time for the video card. The higher the level of anti-aliasing the more the video must work, and more video RAM will be used.
It is one of the aspects of video cards you need to just try. However, if you are experiencing low frame rates with anti-aliasing disabled, then enabling it will make it worse. If you have it enabled and have frame rate issues, then turning it down to a lower lever or disabling it will increase the frame rate.
Overall, there are a ton of things you can do to get more out of your computer. Reducing background processes, disabling themes, disabling unnecessary services, disabling system restore, disabling auto-updater and so on. None of which I can actually recommend, but there are a ton of things you can do.