Re: need a little help fixing lag.
for diagnose: cl_maxpackets 30 cl_packetdup 1 snaps 20
These are standard values I guess so you dont need to reinstall the game.
Check if this dosnt ocurr with standard settings.
Other possiblities: server sucks, you have progs running in the background, somebody in your lan is downloading stuff (also browsing and opening sites with big pictures or vids), somebody in your lan has backround services running that up/dl stuff.
These are optimized settings when your connection can handle it, you will have a smoother player movement etc.
But these highest as possible settings wont cure any connection problems, but make them worse.
So I advice to try default settings and see if the problems come from the config or something else.
He also says that the problems might come from using yitch3