How to understand that an unmanaged switch can not withstand the load-clients?

Question

Iron

There is a server unmanaged switch, most of the twisted pair from it goes to the end client computers, the other part goes to other switches in the same network, because the number of ports on the network switch is not equal to the greater number of computers inside the local network in question. There was a task - to check whether the switch is "poor" from so many network devices? For example, the switch is designed for 48 devices, but in fact it passes one and a half to two times more. Is there a specification, a designation that defines the number of devices that an unsupervised switch can handle, or at least a proven method for diagnosing a network in order to detect packet delays or even packet loss? There are suspicions that on a Windows Server 2008 R2 Standard server, either a software problem with UserGate Proxy & Firewall, or the switch dies, because if you disconnect the server from the LAN, leaving only access to the router, which gives the Internet on the second network card, sites in the browser load noticeably faster. Otherwise, when the server is on the local network - both on it and on client computers, there are noticeable hard brakes on opening sites.

Answer 1

The switch is not designed for "devices", the switch is designed for a certain bandwidth and PPS (packets per second). Given that your switch is unmanaged, this is some kind of household device, and you should not expect it to accomplish anything in terms of traffic transfer.
This is the first. And secondly - in Windows there is monitoring of loading of network interfaces. See how much traffic there is on the external interface of the server. It is possible that you run into an Internet channel.
There is, of course, a proven diagnostic method - this is the removal of the main parameters from switches and routers via SNMP. For home devices, as you understand, this method is not available.