Game already performs amazing, so wonder how much it will help. I'll fire up the game before with the .3 driver and then update and see how .4 performs.
Edit: I'm not going to test it. Because, well DX12. http://store.steampowered.com/news/?appids=289070
I'm taking a hint that these optimizations are meant for the new DX12 API that is now in the game because of this update.
Also might explain why they delayed the drivers yesterday? To wait for this new patch to release.