Intermittent slowness when connecting to printer or server [closed]

        Staff are complaining about slowness when they are connecting to the server or printer. Slowness is experienced intermittently.

I have checked the server CPU load, memory, I/O utilisation and network transfer and it is minimal, this suggests that it is not an overloaded server. Printer is also experiencing slowness from time to time, so a network issue is more likely to be the problem. I ran iperf between the server and client machine which was connected to the WiFi. It initially dropped to zero twice in the first 15 seconds and then was steady for remaining minute. Does this indicate that it may be a network problem? I'm thinking I should run these tests for longer durations and run them from multiple clients. Should I also perform extended pings and check for intermittent packet loss? What other tests can I run?