Stuttering, Small freezes and framerate Issues

[Woopzilla]

EDIT: As stated in the next post, deletion isn't necessary if you verify the game cache integrity.

The slightly tedious way would be to manually delete all the files provided in the zip file from your installation directory.

Alternatively, you could do the heavy-handed approach and delete everything in /sounds/ambience/ + sounds/events/ + /maps/ (Warning: Doing it this way will make you have to download several gigs worth of game files again.)

You can redownload the original files by verifying the integrity of your game cache as plutomaniac suggested (in Steam go to Library -> Right click the game -> Properties -> Local Files -> Verify integrity of game cache).

You should always make a backup copy of all the original files you are replacing before trying new patches out so that you won't have to manually delete or redownload stuff. You would then just be able to copy+paste all your original files back.