You have a lot of ram, linux will try to use most of it, it’s a normal thing. There’s a huge difference from using a large amount of ram when available to NEEDING that amount to run.Try installing both OSes on a machine with 4gb, and see the difference between them. One will be usable, while the other will have a poor performance. You can even push it harder with a 1gb machine. Linux will provide a system with basic functionality, while windows will be unusable.