Here's one: Alongside the multithreaded optimisation and lowering shadows,
If you have a NVIDIA card you can turn down the super/subsample to 0.85, hit alt+f3 and enabling a sharpening filter through geforce experience. Before and after:
(texture checkerboarding is not the result of this tweak, you can only see it because of the sharpening)
This gives a sharp iamge without rendering about 15% of them. You can turn it below 0.85 depending on how FPS hurting you are.