You have a serious installation problem of the sim, it's not something you can fix/improve just by moving a scenery into a faster drive, that will only give you marginal gains.
FYI, I can run P3D 4.4 at 60+ fps on my LAPTOP (granted, it's a good Laptop, with an GTX 1080 card but, any desktop with the same card should run at least the same or better ) so, clearly, something very wrong is happening in your system.
The only thing I can suggest, is to do a really clean install, doing the following:
- Uninstall ALL your 3rd party addons using their uninstallers, if they come with one (look in the "Program and Features" section of the Windows Control Panel)
- Uninstall the simulator.
- Remove ALL these folders:
%APPDATA%\Lockheed Martin\Prepar3D v4
%PROGRAMDATA%\Lockheed Martin\Prepar3D v4
%LOCALAPPDATA%\Lockheed Martin\Prepar3D v4
Documents\Prepar3D v4 Files
Documents\Prepar3D v4 Add-ons
This is a really clean install. After doing that, reinstall the sim and check your performances with NO ADDONS installer.