Maximum cores Unity 5/Hurtworld can use?

I've seen some say 1 and others say 2. I've been only allowing it to use 1 after reading about the drop in performance unless you do otherwise and it did get better, but I still have some instability issues when a high amount of players are on the server (About 40+ players on a 20x server) a few days into the wipe with the large amount of massive bases and people building. I'm tired of the poor performance in this scenario and if there's any other issues that you think it could be please do let me know. The server is becoming full at 50 players pretty consistently in the evening, so I've been working double time on trying to fix this issue and decided to post here to see if you guys know of anything I'm not thinking of or if this is just Unity's limitations.

Server specs in case you need them:
-Windows 2012 Datacenter Edition
-2x Xeon E5520 @ 2.27 GHz (8 cores/16 threads)
-24 GB RAM (DDR3)
-240 GB SSD
-1 Gb Bandwidth / 20TB transfer

 

Thanks! After increasing it to 2 the server has been much more stable and the server fps remaining much higher than before (not as many people on, but I'm comparing it to what it was before updating it). Not sure why I didn't just try this out before asking, but I wasn't sure if there was anything else I was missing.

 

The latest patch is built off 5.3 which has some significant architectural changes in terms of threading. We're still figuring out where this puts us in terms of multi-core servers, but the previous advice of restricting it to 1 core might now be incorrect.

 

After the last update at the linux server just takes all the cores (16), a very high load.
On the equipment with 4 cores is no such. How to fix?