Run the operating system directly in memory for faster performance.
I currently have both files on my computer.
A 32-bit Windows 10 system running on an X86 architecture occupies just 951.5MB of space.
Clarify whether you're referring to the ISO format or a real Windows 10 installation.
I haven’t used them prior and should be included as it, the Win7 is packaged in RAR and its genuine installation for 200MB.
It's not going to be feasible, but there are some cool methods for running an operating system.