The commit size is done by VidMM to make sure there is space when the heap or resource gets evicted by residency - so there is nothing the engine can do about sadly enough. When it’s evicted it needs to be store somewhere and to make sure there is place the memory is reserved already.
Would be good to hear what MS and nVidia have to say about it.
So far, we have not heard any meaningful answer from them. Thanks a lot for your time and explanation. This is a very interesting WDDM design choice. Especially the fact that the user cannot select to altogether disable eviction, and therefore this behavior in case system memory is more crucial than the video memory.