The GTX 285 has 2-3x times the shading power of the 8800GTX, but, the bandwidth is only a 60-80% higher. That's why your results with the GTX285 are roughly 2x times faster than with the 8800GTX SLI system. The bandwidth is not scaling properly with the shading power, and we are getting bigger & bigger screens, and wanting to use higher levels of AA/AF.
I expect to see a huge increase in the framerate with the GT300, if it pairs GDDR5 with the 512bit bus, or at least with that 7GHz GDDR5 memory. In this last case, Nvidia might be lowering the number of ROP units from 32 to 16, and this could be a bad thing if they do not enhance them, or raise their clocks significantly.
I think that your scores with the GTX285 should be higher than with the 8800GTX SLI.
Check my results: http://www.nvnews.net/vbulletin/showthread.php?t=127124
Crysis DX10 VH -> No AA: 93% / MSAA 4x: 80% / CSAA 16xQ: 120%
Overall -> No AA: 75% / MSAA 4x: 85% / CSAA 16xQ: 118% / SSAA 2x: 99% / Combined 16xS: 247%
Hope this helps