Memory Bandwidth ?

The GTX 590 has memory bandwidth around 320gb/s my question is that 320gb/s working as a whole or 320gb/s divided by 2, since its a dual gpu... If you SLI GTX 470 133gb/s will it be 266gb/s or just 133gb/s times 2...

Each GPU is contributing 160gb/s which becomes 320gb/s. Same as if you Xfire or SLI any other graphics card. My 6970 currently is getting 185gb/s. If I Xfire then it'll be 370gb/s. Both GPU's are contributing bandwith to the game. The memory though actually isn't 3gb. When you Xfire or SLI the AMOUNT of memory doesn't double. So you actually have 1.5gb not 3gb. Same with the 6990, it really only uses 2gb.