I upgraded my laptop to Windows 10. Here is my experience
After upgrading, I tried to run FSX. My FSX is just MS version, not SE. After FSX loaded, I can't see the airplane animated rotating on screen as I supposed to see. It keep giving me error ending up my FSX crashing.
Thinking might be because the upgrade issue, so I decide to wipe my laptop and re-install Windows 10 from scratch.
Install FSX with some addon like PMDG and Aerosoft, in heavy airport (ImagineSim Singapore), I got horrible performance. I still see blank screen on the section where you should see the aircraft rotating on FSX main page. I got lots of issue running FSX on Windows 10:
First, when I load complex aircraft, 1/4 screen will become black resulting the FSX reduce the screen. There is nothing I can do about it. However, it doesn't do it when I load stock aircraft.
Second, the rendering is not smooth resulting in lot of stutter. The FPS is quite low compared when I run it on Windows 8.1
Third, I don't think FSX is optimized on Windows 10. Who knows what other addon that won't work on Windows 10?
Conclusion, I don't think it is good idea upgrading to Windows 10 if you are planning to use your PC to play FSX for now. How about P3D? Since P3D is FSX based, there is chance simmer will experience issues after upgrading to Windows 10. It is safe to stay away until the vendor start developing to optimize Windows 10. Keep in mind that if it works solid on Windows 7 or Windows 8(.1), don't mess around with it. Keep it as it is. "If it doesn't break, don't touch it!"
Thank you