Originally Posted by Blameless
It probably thinks the performance penalty, or vmem usage will be too much. A few other games do this as well.
Just force AA in the drivers.
That would be cool if the game is actually that 'smart' ... assuming it's intelligent/accurate in it's assessment, that is.
Also, to the OP, multisampling AA, especially at 2x AA, may not actually hit performance enough to be really noticeable. Try supersampling instead and I would say if THAT doesn't hit you with a penalty, then neither mode is probably working.
Personally I don't like to use the CP to set any particular feature that the game has in it's own settings ... but that's just me, the way I was learned, you might say.