Am 13.11.2018 um 19:46 schrieb Axel Davy <davyaxel0@gmail.com>:

I assume on windows, OpenGL, d3d, etc all allocate in the 2GB. Thus I believe most of the difference is the space taken by the mapped library codes (llvm, libx11, etc), and eventually some libraries allocating more space than they should (pulseaudio).

As far as I understand on Vista and later D3DPOOL_DEFAULT resources don't consume client address space as long as they stay in GPU memory. When they get paged out of the GPU, they reside in the app's address space.