I play FSX with Aircraft in Ultra High, Scenery too, and Clouds in Medium High..
I get a max of 40FPS.. on Galeão (Brazilian Airport) i get of 25 to 30.. it works good, but my graphics.. i don't know, i see some pictures that have reflect on aircraft.. on the turbine, etc.. i liked it. The scenery is not so good too..
My configs: Intel Core i5 650 @3.2GHz (2CPU + 2 Hyper Thread) ZOGIS GDDR5 GT240 1GB 2GB KINGSTON RAM (I will put 4 or 6GB..) MOTHERBOARD I5 1156 GIGABYTE H55M-S2HP HD 320GB Samsung 7200 RPM + Seagate 250GB..
More aboutimproving graphics gt240
More ram, 4gb + should help a good deal.
The GT240 is not a very powerful card. You should be able to get better image quality and higher resolutions by getting something more recent.