Can you better define "getting clobbered"?
How much video RAM is on each card?
Precisely what options/config choices are set in "Video Settings", "Options->Graphic Details", and "Options->Graphic Details->Advanced"?
What about any anti-alias settings outside of the game?
My initial guess will be it is not performance related, but resource related.
By the way, there is a very good chance the NVidia suppied SLI configuration file, for Aces High, is no longer correct with this new update.