The Inq's got the details on the extra work that went into R520's memory controller. Cool stuff.

"As soon as memory prices goes down ATI might introduce a 1024MB card, not because you need it, rather because it can. The R520 memory controller can address 1024MB of memory and as far as we know, the G70 can only address 512MB. We might be wrong about that are we're prepared to be corrected by the Graphzilla spinCrew."