Just an update, Today I did a stream with MSFS and FPS was not normal and seems to be around 20 FPS even just over the water and not smooth.
It does help when using CPU to encode instead of using my GPU 
that has helped as that has taken 10% off from using GPU load.
After more playing around, I turned DX12 on and noticed that there is far more performance and far more stable to point and saw that GPU load was at 0% XD As soon as OBS is on She’s going to 60%
As soon as I thought it was all good, Loaded in the PMDG 737 and it’s bad FPS 
They spawn another aircraft using the devMod tool into a Cessna 152 and full FPS and smooth, then after 5mins it’s good back to bad FPS again…
As thought I seen DX12 made a big different it does not