Maximum live sessions and user capacity

Question

Hardware and OS: CR50iNG ( SFOS 17.0.6 MR-6 ) 
 I want to know the number of maximum user which can login simultaneously and be active connections. 
 Also, I am using DMZ zone feature in it and all ports are used. 
 During heavy load time: 
 CPU: 30% 
 Memory: 65 to 80% 
 I get a yellow mark on performance icon and average load is above 4.5 
 What is the reason?

Aditya Patel · Answer

Hello Saquib Akhtar, 
 That would depend on the type of users are using your online resources. As per my recommendation 30 to 40 users/devices with SFOS firmware with all features enabled. I would advise you to contact your local vendor or Sophos Partner. They may assist you with an hardware upgrade, before that try to open a case with Sophos Support to check if they are able to improve the performance by configuration adjustment. 
 My recommendation is to apply DOS settings as mentioned below for UDP and SYN as per the snapshots attached. This would allow the traffic to manage flooding in your network as flooding would contribute to performance issues.