Choppyness

I am not sure of where this thread goes, but since I have R1Q2, I guess I'll post it here.

About a couple of months ago, my Quake 2 was running fine and everything was very peaceful. Then, all of a sudden, it starts to become choppy (I did not have R1Q2 at the time). If i press the attack/shoot button about 5 times, only one thing will come out of my gun. Also, whenever I look at the water, it moves, then stops for a brief moment (maybe half a second or less), then it moves again.

I have cable internet (comcast digital cable), and rate is at 10000, cl_maxfps at 90. Does anyone know how I can fix this problem. It is nearly impossible to play with the few-second delays.

I must note that I do not lag on my own game, I only lag whenever I join a server.