They usually don’t? If they did, they would have just crashed. If they are still running, then they allowed themselves headroom. The real question is who gets t

They usually don’t? If they did, they would have just crashed. If they are still running, then they allowed themselves headroom. The real question is who gets to use that headroom and how? What happens when the administrative processes use “too many” resources? There are tons of tools built into modern OSes to manage prioritization of processes, etc. Whether it’s worth the tradeoff for you to deal with the operational overhead of harnessing those features is up to you.