Ur having two similar 7900's like GPU's running at 500/1200 .. i think its quite good enough .. maybe not as good at the 7900GTX SLi .. but these should be around the same price as a single 7900GTX ... also .. each core should have its own 512 MB 256 bit mem. ... and being joined together like siamise twins .... its like 1 GB 512 bit blazing fast mem. .... a little oc can really do wonders ...
Nah it will always be 512MB 256bit memory.
In SLI memory does not doubles. the GFX memory is still only 512MB as content of memory are duplicated for both the sets. They hold same information and the max amount of information that can be stored in onboard frame buffer is only 512MB.
And this card is actiually slower in games than 7900GTX that does not support SLI.