TF2 lag help!

I have been getting some serious lag ever since the soldier/demo update. If I get in a fight with more than 4 people it seems the game will start to stutter. Projecticles appear and disappear and its just downright unplayable but in a 1 on 1 fight everything goes well. tuning down the graphics did nothing so Im kind of hopeless here... Any tips? Re-installing is the last thing I want to do since itll take some time to download. The wierd thing is that certain servers will run perfectly every once in awhile but genrerally this is not the case.

 

Sounds like its nothing to do with the game but your net connection, make sure you pick a low ping server and that your not downloading anything in the background at the same time.

 

The scoreboard shows me a ping of under 80. I am positive that nothing is downloading in the background. Other games work perfectly with no lag. Also, TF2 crashes. And this problem was never present befors the update.

 

Hmmzzz, pass then. If you have a multi core system try turning off the option to run it on more then one core, it can sometimes cause issues.

 

I shall try that. I disabled v-sync which helped quite a bit. Thanks for the help.