I'm having an issue where whenever I connect a switch between the wall and the machine, network speeds are significantly slower. It almost seems like they are reverting to 1Mbps speeds. At first I thought it was the switches themselves (they are 10/100 Netgear FS108's) but I got different ones and the result is the same. Plugging directly into the wall (and by wall I mean a bunch of Cisco Catalyst switches) works fine. I tried changing the NIC settings to auto-negotiate and 100Mbps Full Duplex, but it didn't seem to have made a difference. These are all unmanaged switches and the activity lights on them show them as being in 100Mbps mode.
Speed tests show only download speed affected. I also tried different ethernet cables.
Would anyone know why introducing the switches degrades network performance for all machines connected to that switch?