I’ve been pretty surprised at how light it runs. I’m running a single-user instance and have a pretty decent amount of subscriptions to various different instances. I have it running on a thinkserver with a xeon at the moment but, even with like 10 other services (mostly chat protocols–zulip, synapse, thelounge, among other random things) running, my load average never breaks 1. If you don’t plan on having tons of users, you could probably get away with some pretty impressively modest hardware.