Roblox in a virtual machine vs MultiRoblox
A Hyper-V Roblox alt or other VM isolates Windows. For FPS, a VM is usually worse than extra Player windows on the host.
What a VM actually gives you
Hyper-V, VMware, and VirtualBox run a second Windows. That is real isolation: different disk, different malware surface, different GPU path. GPU passthrough is painful. Most VMs crawl in 3D.
What MultiRoblox gives you
Every client stays on the host GPU. You get playable frame rates and no second Windows license. You do not get OS isolation.
Pick isolation or frames
If the job is “I want an alt window,” use Store plus Player or MultiRoblox. If the job is “I need a clean OS,” use a VM and accept the FPS cost.