[Silhouette]

People are running VMs on their laptops so they can test things in an environment similar to production without having to run extra servers for every developer/sysadmin to test with.

Sure, but that immediately raises the next question of why those VMs are so big...

[wahern]

Yeah, the fixed cost of a VM context is on the order of kilobytes in the host kernel, megabytes in the guest kernel. And with VM balloon paging a guest VM acts much like a regular process in terms of memory usage. It's not VM usage that hogs memory, it's the applications, regardless of VMs.