VaM uses the Unity engine and that uses PhysX. However, the Unity developers were so intelligent and took the nVIDIA PhysX, stripped the GPU support, stripped the multi-threaded support and hard-coded it into Unity so you can't the nVIDIA PhysX even if you want to.
TL;DR: Unity PhysX is not able to run on GPU but just a single CPU core.
TL;DR: Unity PhysX is not able to run on GPU but just a single CPU core.