I had a network speed issue (mesured ~10 Mbits/s but should be 100 Mbits/s) using HP workstation with Windows XP SP3 / network card Intel Pro VE 100 connected to a second level Cisco Catalyst Express 520 Switches. Second Level Switches are connected to the central Switch Cisco Catalyst Express 520G at 1000 Mbits/s using uplink port (1000 Gbits/s).
Central server is connected directly to the central switch at 1000 Gbits/s.
The same test connecting a workstation (100 Mbits/s network card) to the second uplink port 1000 port, XP report a 100 Mbit/s link and the test report a correct bandwidth !
Setting port speed / duplex at network card and switch doesnt help
Trying with another network card (100 Mbits/s) on such workstation doesnt help.
Doing a test with another PC with a 1000 Gbits/s network card report a link at 100Mbit/s and the test report a correct bandwith ...
So at this point I dont know really if this is a switch or network card or OS issue ?