Many Mastodon server users and admins have mentioned that the load from all the new users is causing a strain on the system -- large outbound queues, delays on messages, slow page load times, etc.
The good news is that these problems don't have to be solved by buying a more powerful computer.
The Mastodon software uses an old (circa 90s and earlier) way of organizing its code, which I like to call "one-thread-per-request with blocking IO"