You know that when you crossfire the 4850's you still effectively only have 512MB of virtual memory right?
where did this horse poop that 512mb on the ati cards wasn't enough at 1920x1200, I can name two entire games that tend to use more at that res. GTA4, which still runs like horseturd on a 4870x2 at that res with everything at max which is what requires that much memory, and grid, which still plays fine at that res with 512mb memory. I can't name another game that needs more memory.
We still need some new reviews comparing the current 4870's the 512/1gb versions as the reviews on the 1gb launch showed it was faster, but slightly faster and at all resolutions, when below the 512mb threshold there was no reason for it to be faster. most likely the newer cards simply had better timings on the memory which would account for a similar speed boost across resolutions. IF the newer 512mb cards around have memory with better timings they could be just as fast, you wouldn't notice the difference between them anyway.
4850 is easily the best value price point to buy, and crossfiring 2x512mb versions is also hitting pretty much the best price point you can. I got my 4870x2 when it was £300, but since prices went up really the 4850 is the card to buy if you want value for money rather than e-peen.
Take a look at this,
http://www.bit-tech.net/hardware/2008/12/18/first-look-nvidia-geforce-gtx-295-1792mb/4#Scene_1
on Fallout 3 you can clearly see the two resolution options that cause it to go above 512mb memory used 1680x1050 with 8xaa, its fine again and ONLY 3fps short of the 1GB version at 1920x1200 with 4xaa (8xaa is a huge hit and looks almost identical) and again at 1920x1200 with 8xaa it drops massively. But ath the 1920x1200 with 4xaa its clearly faster(5%) even though its NOT a memory size limit.
This repeats itself basically across all the games, a memory limit is shown when it takes a massive hit between resolutions, not a small expected drop from simply needing more horsepower. But in all games even without a memory limit the 1GB version is normally 5% faster, its NOT the memory size. But in lots of situations the cards are neck a neck(crysis) and most situations its only a 5% difference. The few resolutions it gets spanked at are 1920x1200 and 8xaa. I wouldn't pay a shedload more for a card just to use a very slightly higher AA level. 512mb is NOT a limit at that level and in crossfire games 2x4850 will be faster than a single 4870 1GB except using unnoticeable IQ levels. Yes you can see the difference between 4 and 8xaa when you blow up a 1" square of a screen shot to encompass the entire screen just for review purposes, in real life you can't see the difference.
thanks again all 
