After testing that theory, I really don't think I need to worry about that, uri_ba.
I switched Vsync off, and suddenly I have the following astonishing framerates.....
Cockpit view: 85-105fps
External view: 150-200fps
In addition, the strange flickering that I used to get on screen whenever I moved the viewpoint has
vanished!
I can only assume that I must have always been using Vsync. Presumably, the fact that I had the monitor set to 75Hz resulted in those 75-80fps previously? The only puzzle is that I thought I had set the monitor to this refresh rate after the reformat, but maybe I haven't....
I will check that out right now.
EDIT: Yep, the monitor refresh rate was still set to 60Hz. I have changed it to 75Hz, but I will keep Vsync switched off, because I would rather avoid that flickering issue that I had.
I'm rather pleased with that "discovery"