Unreal Tournament 3 @ 1920x1080P
9800GTX SLI 16xAA/16xAF ((4xAA memory footprint))
9800GTX SLI16xQAA/16xAF ((8xAA Memory footprint))
GTX 280 Single
16xAA/16xAF ((4x memory footprint))
GTX 280 Single 16xQ/16xAF((8x Memory footprint))
Now. The GTX 260/280/8800GTX at this resolution. Wont offer identical performance obviously. But they will not show the kind of drop off you see from the 9800GTX. I have seen the 8800GTX pull about 18 FPS at 16xQ settings here. The GTX 260 pulls about 28 FPS. The 9800GX2, 9800GTX, 8800GT, All do exactly what the 9800GTX 16xQ screenshot shows. Once you enable SLI on the GTX 260/280/8800GTX configurations. These framerates raise dramatically. Why the 9800GTX, 9800GX2, and 8800GT cards suffer and are unable to expand with SLI. So yes my Bias in this case does come from an SLI perspective. When you cant see any gains with SLI on what would otherwise be playable SLI settings due to having inadequate memory. I think people should know about it.
Now if someone comes to me at slizone and asks me why this is happening on their 8800GTS SLI setup. Which screams at other settings. All I can tell them is. "Sorry mate. You ran out of memory. Tough Break". When shopping now there are simply better alternatives. Which is why I think so highly of the GTX 260. It will not have problems like this in its immediate future. And I expect to see it alot from the 512 meg DX10 SLI configurations alot.
The summary of my thoughts is. A 512 card Nvidia card can do in a pinch. But if you really dont want to compromise. Spend a little more on the 260. You wont regret it.