Someone ran a modern Linux OS on a 30-year-old CPU, and it's surprisingly usable
(www.xda-developers.com)
Its amazing how much less resources linux uses on my laptop compared to windows. I still use a lot of ram but that is from applications and I don't have to worry about the os hogging so much. I can also reduce my gui effects if I want or such to get more resources but it uses so little I have not had to.