I have just completed a take off and landing at Brisbane airport v2 with Cityscape Brisbane re-installed, flying a Rikoooo Qantas 747, taking off from Rw 01 and then over flying the City at 3500 ft before landing with no problem.
I have reset Ultra to High-2048x2048, Anistropic 8x and 4xMSAA, target FPS set at 50, during the flight the FPS averaged 45FPS, the CPU over the City was on 35% and my GPU at 5%.
The CP = a Intel Core i7 9700 (Coffee Lake) and the GPU = a ASUS NVIDIA GeForce GTX 1080ti
I am happy and for me the issue is resolved, thanks for the replies.
Jacob