These is nothing wrong with SLI working with AA. However, in Jose's case and to extension in the case of FS9, SLI is not working on rendering except AA. IMO, this is an over kill.

But there is more games in life then FS 2004 and I think it will not be the slightest bit overkill for FSX with 2x7800 GT:s in SLI ;). I have no dreams about being able to max that game out with my upcoming overclocked Opteron 170/2x7800 GT SLI setup

Y'all might want to check out Steve's post for the low down on SLI and why you are seeing what you're seeing: http://www.steve-lacey.com/blogarchives/20...imulato_6.shtml.