[dkasak]

You'll be thrilled to know this pretty much isn't true anymore, even with Synapse. My instance is running on a cheap Hetzner VPS with a not very powerful CPU and is currently using about 700M RSS and not much CPU. And I'm in a lot of rooms, some of them quite large and high in traffic.

I'm also not even using Synapse workers at all, just a monolithic instance. Splitting the setup into workers would buy me an additional speedup if things got overly slow.