A performance patch? There's hope for me yet!
er, I actually got it backwards...this is the one with mostly content improvements like better MP, better AI, editor fixes, general bug fixes, etc. There are still a few performance fixes but IIRC they were already planning on a more performance-oriented follow up patch. I got confused with the FXAA being included. It seems they're testing out the FXAA with this patch; then possibly implementing it further (i.e. UI controls) for the next one.
Either way you can check out all the changes here:
http://www.arma2.com/beta-patch.php (latest betas + changelogs). Just note that not all changes are logged...problems caused from previous bug fixes are not mentioned.