S!
It is. The thing goes back to original IL-2 and had email exchange with Oleg and programmer of IL2 about it. IL2 is NV optimized due various reasons. Period. On the other hand it could be hard to press AMD to make any specific changes to their drivers for a game over 10 years old when there is a ton of "boom headshot" games that draw most attention
I can set my card as NV in IL2 setup but if looking at the console you see that the game reverts to a generic 3D algorithm no matter what. Same applies to water, set it to 3 or 4 and you end up with 1.
Also the slight issues with AMD seems to be the water mainly. I benched this a lot lately and it seems that the water itself is a piece of cake for AMD but when Perfect is enabled the sky reflection moving on the water surface causes slight stutter at certain angles and loss of FPS combined with water splashes. This was not the case with NV card I used.
Anyways if TD could check this then it would be nice. If too much of a work then no can do. Yet for one game I do not change my GPU, other games run perfectly with AMD cards