Would entirely depend on what your starting hardware is like.

My 8 core desktop with 32GB of ram would do less then the HP DL380 with 24 cores and 192GB of ram.

It would also depend which hypervisor you use. Microsoft Hyper-V would likely run worse then ESXi or qemu.

How would I approach this? Start with something like damn small Linux or Alpine Linux to start with the smallest footprint. Install qemu and allocate everything to the VM. Rinse and repeat untill I get an out of resources error.