Well, your Pc seems better than mine and ACAD here doesn't act laggy. I'm not quite sure what can be the problem.
If it was a wireless problem you'd have problems when opening, closing or saving cuz it's when ACAD loads the files you'll be working on.
My case is similar our sever is on a wireless computer too, and ACAD acts normal, the only problems I've had are the mentioned above with the drawings (when my boss forgets his computer is the server and just turn it off).
What ACAD version are you using?