All of these new cards have been bench marked head to head against each other. With the ATI 4870 preforming 75% of the GTX280, and the 4850 preforming within 1-2 fps of the GTX260. In this review they will be testing both Crossfire 4850 &4870.
Being that the 4870 is half the price of the GTX280 and 75% of the performance, It should be interesting how one card preforms as well as a single card.
Nvidia is still trying to get more sales of there new cards, so that is why the had a 30% drop in prices for the GTX280 and 260. The GTX280 will now be around $499 and the 260 will be around $299.
All in all the 4870CF setup beats them all in all of the test except for Crysis at 2560X1600.
The review can be found over at Vr-Zone.com