We posted this information on the PlanetBattlefield forums, but one of their admins decided it was not worthy of being on the site. Sure, you can find this information if you dig way down into many different posts, but we put it in the first post for everyone to easily find. Oh well. They dont want you to know, but we do. This is one possible fix for the lag problems experienced in Battlefield Vietnams 1.1 patch.
Add the following to your Battlefield Vietnam/ Mods/ BF Vietnam/ Settings/default.con with a text editor:
Game.soundbuffersize 400 (you can go higher with this if you want to play with it some – some guys have it set as high as 1000, I think I set mine at 400 or 500, I cant remember)
and to the videodefault.con in the same folder change “allowallrefreshrates” from 0 to 1