then the complete GSX program does not work anymore (no GSX menu in P3D)
Of course it wouldn't.
That wasn't to suggest a "fix", it was just to test it in a different way, to be sure the issue IS caused by GSX in the first place because, after your report that seems to indicate you have the latest version, I'm not sure the problem is GSX.
I install the latest version of GSX and install NO updates.
Install GSX WITH updates, and please try to do what I asked instead. If the fps doesn't drop anymore, I would like to have a look at your system with a Teamviewer session because, since nobody has reported this, it's surely some kind of unknown conflict with some other software, which AFFECTS only the latest GSX version, which we would like to know, if there's a chance to fix it, and reverting to using the old version is not the right solution and it's not helping anyone.
Instead, if you disable (JUST disable, NOT uninstall) GSX, in the way I asked, and you still have the fps drop, at least we would know for sure the problem is not caused by GSX.
