I used to have horrendous lag on ranked servers for 5-10 mins every time a new map was loaded (only for one round). I am talking 10-20 fps lag or sometimes worse. This usually resulted in me trying to find a place to wait it out or just getting killed over and over. It also happened on unranked servers but only for 2-3 mins. I got fed up with my McAfee antivirus/spamkiller services (for other reasons) and removed them from my computer. Now the lag doesn't happen at all! It simply isn't there and I can play the game like it is meant to be played. In the words of the lovable Stimpy...happy happy joy joy happy happy joy joy happy happy joy joy... I hope this helps someone out.
What anti-virus do you use now? I find Norton is pretty good on performance, I have Norton Anti-Virus 2003 updated to current and I run it any time my computer's on and as far as I can tell it never slows down my gaming.
I always thought that FPS and lag were two different things? Like either it was low fps due to software/hardware conflicts, or lag from the net/server. I have McAfee and only experience the usual level load choppiness in the beginning of the round, after that any choppiness is from lag. Did you ever completely exit out of McAfee before playing? That may sound like a stupid question, but i didnt know that by just getting rid of its icon in the icon tray did not close McAfee entirely. It has to be done from the task manager.
I use Mcafee anti virus and it doesn't effect me as far as lag nor Fps. I don't exit out of it or my firewall software.