My Interpretation of the results:
TLDR:
X3D CPUs do perform better in some cases while not lagging behind much in others. They are definitely worthwhile if budget is not an issue.
SMT should be enabled, as disabling it provides at most a few % of performance uplift, at the cost of more than 50% reduction in world generation speed.
Limitations:
I don’t have a large server with many online players to test out with so these are all a bit limited in what they test.
Going into the test I kinda didn’t know what to expect, as looking at other benchmarks show that some tasks really like the extra cache while other tasks get hurt by the lower clock speeds of the X3D parts.
World Generation:
This was just included for fun, and you can mostly ignore this one for server hosting. World generation in the optimized forks of the Minecraft server are entirely multi threaded, so more cores = better. From the test results it seems like it likes clock speed over cache, as the normal 5800X is slightly faster than the X3D parts.
Disabling SMT hurt this one quite badly, since world generation was limited to half the number of threads. Since the thread count stays below 8, enabling SMT actually allows the process to use 4 cores instead of the 2 with SMT disabled. This explains why the time is almost double with SMT disabled.
Entities:
I really don’t know why the 5800X3D had a performance discrepancy with SMT disabled. Perhaps the X3D part is also somehow disabled when SMT is disabled??? This test is supposed to be lightly threaded so I don’t really know what is going on.
Both 5800X results and the 5800X3D without SMT results look like they lie within margin of error, with the 5800X3D with SMT enabled leading clearly by a significant margin.
Redstone:
No surprises here, higher single thread = better. Disabling SMT on both chips show a measurable performance increase. The higher clocked normal 5800X also managed to lead the lower clocked 5800X3D by a small margin.
Web Map Rendering:
This one was mainly thrown in for fun, as I don’t think you should be considering this item as an important factor when choosing a server CPU. Players are going to complain a lot when your server is lagging, but less so if the web map updates slow.
The process involves generating data from world files, then compressing said data using gzip. What exactly makes the 5800X3D slightly faster is up to people who are willing to go read BlueMap’s source code to figure out. What I suspect is happening is that more of the data required can fit in the cahce, leading to a slight increase in performance here.
Conclusion:
The X3D CPUs might offer a significant advantage in certain cases. However there is no clear cut winner as for which is better. If I were to spec out a Minecraft server build tomorrow, then I would go for the X3D part as it does provide a significant advantage in certain cases while not lagging behind much in others.
SMT should be enabled, as it only offers a slight advantage for certain cases while drastically hurting others.