RageMouse :
Xyos :
Lag as in network issues? I assume you mean framerate drops and dips then? A multitude of issues could cause this, it does not help that your system is extremely dated. That could simply be the issue right there...
No framedrops just rubber banding and teleporting back to where I came from so network issues I guess.
While you are playing, alt-tab out then open up the command prompt and type "ping google.com -t" without the quotes. If you see your ping spiking over 120ms, then you may have problems with your internet connection (wifi adapter, router, modem, or the service itself are all possible points of failure). Most decent internet connections will have ping somewhere between 20ms and 60ms to Google. What you should be concerned with is if you are getting 35ms, 37ms, 35ms, 1756ms, 40ms, 34ms, etc. The spike up to 1756ms would be an example of a lag spike.