Graphic settings DX11 notepad ini settings question

[Achilleslastand]

I found these 2 lines and am wondering what they do if anything?
; Use more advanced GPU features which can cause some drivers to crash
TerrainUseAdvancedGPU = 0

I changed the 0 to a 1 and the terrain does seem to look smoother although it might be just the placebo effect.

I also noticed this line....
; Allow cheaper shadow blur for DX11.
AllowCheapDX11ShadowBlur = 1

Anyone know exactly what these do?