We have a new Dell PC(T3400, 4GB ram, Dual CPU, WinXP x64 SP3) that randomly drops from 1Gbps to 100Mbps. It is connected to a 3Com 48port Gigabit Ethernet switch.
We have tried:
- changing the PC patch cable, switch patch cable,
- changing switch port,
- changing connection to another 24port GBE switch,
- reinstalling NIC drivers,
- changing the LAN data patch point,
- If I force the managed switch port to be 1Gbps, the PC is unable to connect,
I added in a PCI GBE NIC and the PC connection is back to 1Gbps.