Well I set up a Multiboot on my Lap since Windows 10 had this awful Mouse Bug I talked about earlier, which I couldn't fix yet.
However, even though I had to cap at 70 fps (using Riva Tuner) in WIndows 10, cuz otherwise it would have been unplayable with the mouse, it at least reached 140-150 fps (when uncapped).
Now on Windows 7 it only reaches 100 max. (best was 112 if I'm correct), so it actually can't be my hardware.
What I tried already:
-(usual) deactivate V-Sync
-uncap fps (even though my cap was 150)
-optimize NVIDIA-setting after performance
-change Windows settings performance-optimized
-put down all Freelancer graphics
-set up Freelancer and Discovery again (without blooming)
-run with admin rights
-drivers are up to date
might sound stupid, but works for me: Bloom mod makes everything dark in normal setting. It also takes ~ 30 FPS away from me. I think the shortcut to deactivating it is: SHIFT-F12 or CTRL-F12. Can't check atm. The bright version gives me a lot more FPS.