Memory Pool Settings

Hello all, I've got 2x HD 7770s in crossfire. They both have 1 gb of vram on board, and I know that in a crossfire configuration, this vram is essentially shared for a total of 1 gb.  If I am understanding this correctly, that means that my memory pool settings on games like Bioshock Infinite can only go up to 1024 mb.  Is this the case, or could I use 2048 mb of memory pool?  I ask because upping my mem pool dramatically reduced stuttering in game after applying the steam launch protocol to read from the ini.  

Thanks for any reply!

If you have two 1gb cards, you can still only use 1gb of memory. 

Alright thought so.  Thanks for the quick reply!