Yeah I just maxed out my updates slider because I thought it would generate the clouds. I turned it back down to 2 notches from the right, the shadow texture to 512, and then maxed out the other advanced options and view/object details to 4 miles. With that, I started out with a frame rate bouncing around in the 40's, but after I got away from the airfield and in the open country my frame rate leveled off at my normal 59. This is all without seeing or flying through any clouds, so who know what would happen then.
BTW, both tests occurred off-line on NDISLES center island.