I flew over New York last week (SU4) using the Icon plane, took a tour round the surrounding area and landed on the water close to the Statue of Liberty. I was getting a nice smooth 35 fps with very little stutter and the photogrammetry scenery looked superb.
Tried the same trip today with the Icon and it looks just awful, most of the buildings are popping into view as I look around and look nowhere near as good as before.
The draw distance is now hopeless (I have every setting I can set to high or ultra apart from Render at 100) and flying NW over the East river with central park in front of me I can just see a desert with no buildings rendering past the Hudson river. Last week I had buildings out to the horizon.
London is just as bad, looks like a desert, anything over 2 miles away is replace by a sandy flat landscape into which scenery magically appears as you get closer.
So for me SU5 = 5 more fps but totally immersion breaking scenery redrawing with lower quality textures and over exposed whiteout clouds.
Are you seeing buildings out to the horizon and not popping in and out of existence when you fly over New York and London?