Netowrk switch port speed check

Hey everyone
I have a client that has 4 x 24port 10/100/1000 network & Cisco L2 switches. I need to be able to check exactly what each computer is conencting at. The client is saying hardware is having slowness issues so i need to check speeds on each port.
I know PRTG as an application, but can’t find a full version.
Answer #1
Solarwinds is a good application.