Quick flight over england mission.
With my low spec machine I noticed a good gain in FPS. I am running land detail low but gained about 10-15 fps then pre patch with the same settings. What I have noticed which I also had before patch was a texture ( loading ? ) problem. See in picture 1 the Hurricane has low texture detail. This just changes from high detail to this for some reason - while at the same time the Hard drive has heavy loading activity and the stutters occur as well as a FPS drop.
While in this picture the graphics are back to higher resolution on the Hurricane some seconds later with higher fps and more objects visible.