Turn off: SSAA, Motion Blur, Lens Effects

Set Resolution of Cockpit Displays to "1024" instead of "1024 Every Frame"

Turn Clutter/Grass to something more sensible, definitely below 500.

Set Terrain Object Shadows to "Flat". Set Cockpit Global Illumination to "Off".

Also do the shader recompilation dance.

With all that you should get much better performance at almost equal visual quality.