Update on this. I have unchecked everything (right down to Aerosoft Majorca, including all Scotflight, UK2000,Earth Simulations inc. IOM) except GenX. no difference. I've renamed any Scotflight files ie;Oban, connel bridge,fences, ai traffic etc.
The only time it is normal is if I uncheck SIM720 (which I really don't want to do ) OR I reduce display/scenery/water to none (off) or low1.x which I really don't want to do either. My normal setting is Max2.high