Shadowcat: Does the GOG version not still use Zeckensack's Glide wrapper? It certainly did originally, and there's no changelog for the game indicating a switch to nGlide.
The contained configuration tool says nglide 1.02 so i assumed it.
Sadly after playing along i discovered that the nglide update didn't solved the Problem it only reduced it, quite a bit but still game breaking in higher levels where every PBC count.
Next thing i tried was reducing the framerate with MSI Afterburner as sugested in another thread (didn't work).
- Remove the Vertical syncronisation in the nglide configurator (it was sugested this will override external settings, I tryed both without results)
- installed the
MSI Afterburner. Important the RivaTuner Statistics Server, bundled with the MSI software does the framerate cap and on screen overlay.
- The RivaTuner will start with the afterburner and a tray icon will apear here you can set the frame rate.