Is the Rust Legacy Server Multithreaded?

Hey Folks,
Since I could not find anything that confirmed or denied it on Google, I was wondering if any of you knew whether or not the Rust Legacy Server was Multithreaded. In other words, would I be better off renting a multicore dedicated server than I would be just renting a regular Rust Game Server through a host? Wondering this because the server seems to get a lot of lag, limiting what I can do with plugins. Thanks for your help!