OK, since installing the patch Dolby 5.1 is no longer available and changes in the sound options is changing the windows speaker config !! Plus there are missing sounds when playing in surround mode. e.g. Can't hear enemy fire.
This is with a 5.1 speaker setup and an Audigy 2. Fresh install of Far Cry! !!! Did not have this problem with previous versions.
Also performance has no increased but nevermind that, sound is more importent !!