FSX isn't graphically intensive. It's CPU intensive to the extreme though. I get about 8FPS with all settings maxed, and about 10FPS with all settings to the bare minimum. And I mean everything maxed and everything minimum, including AI traffic, cars, 3D clouds... everything.
And that's with an X800XL ATI video card with hmm 128 or 256MB of memory and like 8 pixel pipelines. Had FSX been graphically intensive that really old video card would have choked. But instead the framerates changed by a whopping 2FPS therefore telling me that my CPU cannot handle FSX at all, at any setting.
I just don't think ur video card can handle even the min of fsx. With two 8800 gts 512 in sli, with everything maxed out, I mean everything I can get about 20 fps. With everything at min I can get about 80fps. I do agree that having a better cpu would help, such as a quad or at least a faster dual.
I see what your saying but I'm not sure that you understand how flight simulator uses the sliders. All of those AI aircraft sliders and car traffic, and boats, and ships, and airport vehicle traffic... and a few im probably forgetting all have a SIGNIFICANT impact on the CPU...that's why your framerates go really high. Test it out set your terrain details and what not up higher and turn everything else down, you will not see a huge drop in frames....obviously some but not a 60FPS difference.
Out of curiosity have you tried the SLI profile on SLIzone? I do not have SLI so I don't know anything about what a profile is, is it just a config file that you stick in a folder or something? Or is it just a document on where to stick settings?