Aha that´s the difference!
I noticed that smaller text on the MCDU can get reeeeeeeally blurry in combination with AMD FSR.
With both iGPU und FSR active the text can get really thicc and very blurry (sometimes it is becomes difficult or impossible to distinguish letters like 0 with 9 or 8 or B) on a resolution 2560x1440.
But the framerate is almost 10 or 15fps more with iGPU on, and without AMD-FSR the visual difference is minimal so I keep my precious Vega11 rendering the displays 
FSR especially on performance or balanced settings is way worse than iGPU on.
iGPU adds a ton of performance with the cost of a hint more blurryness in the MCDU text.
This is how it should look like in real life, very thin (text seem to be almost two pixels thin) and crisp sharp
