Lag Problem

[Goldfishpie]

I'm just throwing it out here in hopes of getting some suggestions as to how to solve my lag problem. It only occur es when I'm traveling with other PCs or there's alto of NP Cs around, doesn't seem connected to any particular time or area. It's difficult to describe it, but it's all jagged and jumpy when I walk, and action and texts are delayed, but transitions run smoothly and aren't particularly slow.
 
I'm running on compatibility mode on Vista and I didn't have this trouble before Christmas when I was playing on the same computer and on the same network. I don't have any overrides or hak installed and I've turned down all my specs. In addition, I'm serve all my drivers (NVIDIA GeForce 8600M) are up to date.
 
So! Any suggestions would be appriciated!

[Mort]

Threaded Optimization turned off? Especially with a GT8800 model.

[meow-mix]

Might be a stupid suggestion, but the first thing I would look at is if you picked a higher efficiency power profile (I am assuming it's a laptop) around Xmas.  Some of the more efficient power schemes nerf your video card.

My one and a half cents, at best,
Meow-mix!

[derfo]

Go under sound settings and move your sound slider all the way to 2D, and set it onto one of the options with 2D in it if possible.