really really REALLY terrible review which is all I've come to expect of Anand after the last few years
There is one game, yes one, which benefits from the extra ram, we all know Grid is the only game to show a real difference above 512mb on an ATi card, and its the only game here to show a significant increase at a SINGLE resolution.
The other biggest increase, Age of conan, is 2.5fps faster low res, 3 fps faster mid res and 3 faster high res. As in, its a common element, it has nothing to do with running out of frame buffer. All the other games also show a common speed increase at all resolutions.
Now most likely the cause is much higher spec ram, they've waited for new memory, from Hynix, they noted this but didn't manage to draw any conclusions or notice that speed increase was apparent when clearly not memory limited. yes the 1gb is good for grid, its the only game I've seen so far that needs that much mem, considering AMD already spanked Nvidia in that game and gave more than playable performance, who cares tbh.
My guess would be tighter timings on newer memory that are different enough to show extra speed at all resolutions. Theres an outside shot they didn't notice it was a higher core clock speed card, it would make sense to introduce an inbetween card with a slightly higher price gap with higher clock speed and better more expensive memory, with lots of overclocked versions maybe they simply got a pre-clocked one, though less likely, Anandtech have gotten crap but hopefully not that bad.
Either way, its very much worth waiting to see if newer 512mb/X2 cards come with Hynix mem rather than the old stuff, if they are faster, and if a price gap opens up with a drop in 512mb price that makes it the better buy.
Anandtech 2 years ago would have spotted the speed increase across the resolutions and actually thought up a reason, these days they really do suck.
Keep in mind also, if thats the case, tighter timings, overclocks might be more limited, though I have no clue how the current 4870's/x2's overclock as it is.
I wouldn't buy for a month at least, more stock, more brands, lower prices, hopefully a drop in the 512mb card price and maybe an idea of why its faster.