No, the GTX 260's in SLI beat the 4870X2.
The 9800GTX+ beat the 4850 and the 8800GT beat the 3870.
The 4870 did beat a single GTX 260 however, and in another run the 4850 beat the 9800GTX+. But keep in mind, big bang II isnt out yet either.
Really theyre gonna end up being really close to each other in performance like they are now.