Anyone getting tons of lag?Follow

I've searched and haven't really found anything that can help.

I am running into tons of lag. Even when there aren't as many people around. I have changed some settings on my end to up performence of my video card, but nothing is helping. I have a Quad core 2.6 GHz processor, 4 GB ram, Radeon HD 5800, on windows vista. I turn off all non essential programs as well. Thinking of getting a new video card, but really can't spend the money at the moment.