3 wired users is not that bad. if they are connected to each ethernet port, that is ok because each ethernet port is one collision domain. Meaning this 3 wired users can send and recieved at the same time.

what I am concern about is your wireless connection if you have one. wireless connection is one collision domain. meaning the more wireless pc connected, the more slow the network will be. all wireless pc will eventually stop and wait for thier turns before sending and recieving.