T&L is transform & lighting, and if it's on the card's GPU (graphics processing unit) your CPU (central processing unit) won't have to worry about handling it (which is why you can get a slower processor if you have T&L). T&L doesn't have anything to do with front-side bus speed, which is different than processor speed. FSB speed just determines how fast data is sent between components of your computer.

the GeForce FX 5200 is T&L capable (I have the 256MB version) but you don't have to have 800MHz whether it's FSB speed or processor speed