UPDATE: I started understanding what the graphics settings are doing by reading this guide. It also pointed out that Volumetric Clouds needs to be turned off.
So after some tuning I decided to publish my settings. At the moment this seems to give the best balance between performance and visual quality on my AMD R9 380 (4 GIG), Intel i5 4690k.
Ignore the in game benchmark as that was when I was in the desert. The most demanding city scenes (at least so far, I’m only a little way into the game) where there are many NPC’s averages around 45 FPS very rarely going below that.
Don’t be afraid to turn down the resolution.
That’s it !