As a matter of interest does the GSX program put much load on the computers CPU and therefore affecting frame rates
It surely doesn't and, when objects are displayed, the impact should be comparable as having 2-3 AI airplanes more.
that is whilst the aircraft is flying
When GSX is not working, it doesn't impact performance at all. And of course, you can verify this by installing the Trial version.
as I have noticed that the Task Manager is showing a program couatle.exe as running.
Having a separate .EXE it's precisely the reason why it does NOT impact performances. EXE programs are automatically scheduled by the Windows multi-threading to run on a separate core (if you have at least a dual-core, of course) and, since FSX never use all cores except when loading the scenery, the whole Couatl.exe is running on a different core than FSX, which means it can't slow it down, even when doing the most complex calculations.
