FSX Performance issues in Windows10 Pro

I might just chime in here and add that I recently took advantage of the free upgrade to Win10 from 7 for our gaming rig. I installed P3D (didn't get as far as installing FSX) into the default Windows drive 'program files' location and had endless problems with it. Rex wouldn't install textures to it, I couldn't get PTA to work, Ezdok would crash, etc etc. I then nuked Win 10, started over and installed P3D in its own custom folder on my separate SSD. It's run like butter since.

I never took any notice of the 'don't install to the program files folder' mantra back in Win 7, but clearly Win 10 does NOT like programs like FSX and P3D in this folder, even when you 'run as admin'.