Hi end GPU for FS9 with max image quality?

If you could comment on how the GTX 570 handles extreme AA supersampling modes and 3d clouds in FS9 and not FSX, I would be obliged... I know FSX works great with Fermi GPU's, but FS9 has different shaders and graphics, and it seems is even less optimized for AA in new GPU's. So, back to the topic I started, the 6950 2gb version I got, works well, but in some cloud situations with 3d clouds overcast and many cloud levels it still drops below 20 fps with supersamplingBUT, I am keeping it because the image in comparison with my GTX280 is so much better even though I had the settings maxed out in the V control panel.

As already stated, I was running FS9 on a i5/750 (no OC) with GTX275 (no OC) and REX Extreme and never had any problems with heavy fps drops in clouds. Flying most of the time level-D 767 and in VATSIM with FSInn. (cost also 5 to 10 fps) using till last month nHancer AA 8S and AF16 but after reading Bojotes alternative for FSX (not FS9) I decided to put in a GTX480 and gives me in FS9 not much extra. Due to the quantum leap in FSX I made the decision to go on further with FSX. Today I brought back the GTX480 back to the shop for the GTX580 Lighting and WOW... Sorry, can't check it anymore because FS9 is removed now.Long story short, If an i5/750 with GTX275 can handle dense scenery, dense REX clouds, heavy planes online with VATSIM there must be your answer. There are long topics about ATI versus Nvidia in Fsim and I prefer Nvidia for clouds.Because nHancer is completely override now with Nvidia Inspector, shimmering was also much better (read less) in FS9.