Note - Due to these performance issues any new service is set up with Spigot, not Vanilla, for the latest Minecraft release once Spigot is considered stable for that version (ie currently a new server will run on Spigot 1.16.3, not Vanilla 1.16.3). If you intend on running a "Vanilla" server, simply do not install plugins and it will run the same ingame as a Vanilla server would - it is not recommended to switch to Vanilla itself but you can if you wish, at your own risk of increased performance issues. To clarify - Minecraft 1.13-1.16.3 versions are **not stable**, particularly Vanilla, and will have a much higher chance for performance issues than older server versions (currently the last Vanilla version considered "Stable" is still 1.12.2 and will remain so until serverside-specific performance fixes are applied in future releases). The Minecraft 1.13 releases were playable, but noticeably poorer for performance compared to 1.12.2 - The main/biggest issues at the time being chunk loading/generation (which persists all the way through to 1.16.3, though it was less of an issue in 1.13 than later releases) and issues with mob AI (particularly the newly added fish mobs). When the 1.14 releases dropped they did resolve the issue with the fish AI causing performance drops - however, a lot of other performance issues were introduced and chunk generation/loading performance took a pretty big nose dive. In particular: - The newly added Pillagers were a cause for major performance issues - it was very easy for a Pillager to get stuck as it moved around and it's pathfinding to go haywire causing extreme performance drops even just from one or two mobs getting stuck. - Villagers were also a major issue with their pathfinding/AI causing performance drops, particularly if they became unable to find their job block. - Leaf decay also caused a drop in performance so biomes heavy on trees were heavy on lag (Jungles for example). 1.14.4 did resolve the worst of the Pillager/Villager AI and pathfinding issues, but it did not improve the performance elsewhere. While the 1.15 releases were noted to include performance fixes - almost of these (literally all bar a few small fixes) were for clientside performance issues and they did not touch on let alone fix the major issues that were happening serverside. In the 1.15 releases chunk loading/generation was still a major issue for performance, and mob AI as a whole started to cause heavier load so mob build ups would also drop performance considerably compared to the same mob build ups on older versions. Unfortunately the Minecraft 1.16 updates did not do much if anything to resolve the major causes of serverside lag introduced in the last few major updates either so the issues 1.15.2 has are still present in 1.16-1.16.3. Suggestions To Help With Vanilla Minecraft 1.16.3 Performance Issues At this time there is little we can suggest if you wish to run Vanilla specifically as the server software itself is the specific issue and will be until a new release fixes the problems. All we can suggest to try and help with general server performance is the same as we have been suggesting for 1.13/1.14/1.15: - Lower the view distance in the server.properties (Files > Config Files > Server Settings on the control panel) to 5 or 6, save changes and restart the server to lower how many chunks will load in around players on the server which will help with the CPU usage spikes. - Avoid loading in a lot of chunks (new or pre-generated) by flying around or travelling long distances by boat/horse/cart etc... - Make sure to restart the server regularly (recommended at least once a day) to unload excess chunks and entities and refresh the RAM usage. - Avoiding the usual potential lag causes such as mob build ups/grinders or large amounts of active redstone etc.. is also recommended. It would also be advised to use Spigot instead of Vanilla (for new services after the date of this post you will automatically be running Spigot 1.16.3, not Vanilla) for their performance patches even if you never intend on using plugins. If plugins are not installed then Spigot will run the same ingame as Vanilla does. When using Spigot it must also be updated regularly to keep up to date with any patches/bug fixes they have issued - to do so simply log into your server files and delete the jar folder before restarting the server (recommended to do at least once a week). There is also a guide here on some optimisations you can make through the bukkit.yml and spigot.yml files to help with general server performance that are strongly recommended to go through, but they will tweak aspects of the game such as mob spawn rates (as that is what they need to do to aid in the performance): https://www.spigotmc.org/threads/guide-server-optimization⚡.283181/ If Spigot with the above tweaks does not help with performance enough then you can also try using PaperSpigot instead with the tweaks to the paper.yml as listed in the above guide. Unfortunately beyond this there is little we can suggest for the ongoing Vanilla server issues - the server version/software itself is simply full of performance issues that would require serverside fixes on Mojangs end to improve, and for quite a while now these issues have been ignored. Plugin Sidenote: If you do install any plugins they must also be compatible with the server version, installed on their latest release for that server version and should be checked for updates regularly for bug/issue fixes etc... Any plugins that are installed on their latest release and still give errors in the console, particularly regular errors, should be removed/replaced without exception - no plugin should give regular errors in the console, any that do will be causing/contributing to server issues regardless of whether they appear to work or not ingame.