Use the free Lorby Prepar3D Addon Organizer from this site
https://www.lorby-si.com/downloads.html
It will create the xml file for you.
Download the documentation on how to do it
If you install scenery outside the Prepa3d folder, you need to put a xml file in C:\Users\[your user name]\Documents\Prepar3D v5 Add-ons
Normally you get the xml file with the download. You probably need to edit the file to point to the folder where you installed the scenery
Prepar3d needs space on C: to unpack the app. If your space on C: is too low, the best thing to do is to temporarily move a (large) map onto another drive. After P3D install, move is back to C:
So, with your 8 threads i7-7700, you actually turn off 5 threads and run the sim on just the remaining 3 ????????
As it happnens, I also have a 7700k. HT on and AF 253. (leaving 7 threads for the sim)
My P3D v4.5 runs perfect.
Try this. Not sure it will work for v4.x but give it a try
https://www.flightsim.com/vbfs/showthread.php?298120-P3D-v3-2-Solution-for-Large-fonts-in-ATC-GSX-ProATC-X-and-other-windows