"Run a modern operating system on 8 GB of RAM? WHICH?"
umm... all of them...
assuming you meant 8MB of ram
you can run a fairly modern gnu/linux distro on less than 8MB of ram
and with older gnu/linux versions you can run it on 2.5mb of ram(i tested
this in a VM)
[Someone asking about running a new gnu/linux distro with less than 8MB ram]
https://unix.stackexchange.com/questions/127869/a-linux-distribution-under-8mb-ram
an old slackware version running on 4MB ram and a 386DX cpu!:
https://www.youtube.com/watch?v=C-VlIZaLxVE
its not too easy but can be done and with some optimizations for the N64 a
gnu/linux distro could run quite well on the N64
also Window$ 95 had a minimum system requirement of 4MB of ram
just to give an example that you can run graphical desktops with this much
ram