Many reasons are affected to your result i try to explain some important of :
At First it's important to know how config your VMs many options are important like : reserved CPU ? Or reserve Memory Or Share it.
How many Vms in your host and when you run your queries how many workloads your host has ? and many other reason like hypervisor config ...
There should be no negative impact on performance esp when you have encountered PFS page contention. Just make sure you dont blindly over create files.
This script from Tigertoolbox (Microsoft Tiger Team) will help.
Depending on the version of sql server you are using, you might need or might not need below trace flag :
Trace Flag 1118 – Full Extents Only ...