S!
Is this PE Explorer a free software? IF so, then worth taking a look
Was there any structure in the dll that could tell anything how it works for various cards? The IL-2 programmer did help with AMD driver issue(blue hue and blocky text) by giving information what to look for in drivers. IF he could be contacted again he possibly could help? That would be great
It is easy to test the stutter issue for example with AMD over water. I set it to 2 and fly over water at around 100-500m. Take external view and look straight down above your plane and you see a slight stutter even FPS is a solid 60fps with VSync. Now move the camera to a lesser angle, say 80-45deg and the stutter is gone. Strange ain't it? Above ground this does not happen.