X-Plane almost freezes (stutter)
Please check this first. When temporary removing (just copy it to you desktop) the plugin XSaitekProFlight folder and start X-Plane again, the problem should be solved. If so then your XSaitekProFlight driver (latest version from Logitech site) is corrupting your X-Plane. The only way to solve this is replacing the win.xpl file in the 64 folder with an older version.
The current driver has the date 09/05/2017 14:32. Replace it with the one from 22/04/2017 09:11. The file in 32 folder should have the date 09/05/2017 14:24 and should be ok even in the newer drivers versions.
Download this file and replace the win.xpl in your 64 folder. Start X-Plane again and everything should work just fine.
UPDATE
After experimentation it seems to be that you can use the latest Logitech Drivers. To do this please only use these 2 drivers for all your equipment and install them in order as described.
First go to your plugins folder (Drive:\X-Plane 11\Resources\plugins) and remove the XSaitekProFlight folder completely out of your plugins. Install 1_xplane_plugin_x64.exe first. After this, install 2_x-plane_instrument_panels_x64.exe. Do not install any other panel drivers! Start your X-Plane and the FIP and Panels should work fine.
2_x-plane_instrument_panels_x64_.exe
Enjoy,
The ArtIT Team