I want to install new Windows because Windows 10 always takes hundreds of RAM sizes. And Windows 10 Light and Dark themes are ugly. I need better for my laptop.
The purpose of computer memory is to be used. Caching more content in memory = better performance. It makes no sense to have hardware resources you don't use.
at a system level Windows 8 is the fastest then 8.1 and 10 [in that order] however both Windows 8 and 8.1 are now finished so your only smart option is 10