I know some people are running Windows 10 on 4gb of ram which is minimum. I know for Windows 11 your going to need at least 8gb to run as well as 4gb is too low to run Windows 11. I know that some people can run some tweaks for Windows 11 to reduce ram usage but I would say Windows 10 and Windows 11 run best with 16gb of ram. I doubt you will notice any performance improvements pass 16gb of ram. I know that ram has really gone up in price so it meant be better for you to get a new computer used then upgrade your ram depending on how old your laptop is. I know there are examples where more then 16gb of ram is useful like with VMware with virtual machines. There may be a video game on pc that uses more then 16gb but generally speaking 16gb of ram is the sweet spot for Windows 11.