I have a Dell PowerConnect 5448 Switch with random workstations connecting at 100mbps instead of 1gbps. This is a new internet cafe with brand new CAT6 cabling. 12 workstations have intel network cards, 28 have broadcom network cards.
If I do a show running config on the switch we can see that the speed is set to 1000 by default for all ports.
One of the PC's that is syncing at 100mbps is on port g33 of the switch. Below I manually configured g33 to force it to be 1gbps.
I then unplugged the CAT6 network cable out of port g33, then plugged it back in so it could re-negotiate speed. Again it came up as 100mbps. I then plugged the machine into a TPLink switch.. it negotiated at 1gbps straight away so it is not the cabling.
The firmware i'm running as of this writing is 22.214.171.124 on the PowerConnect 5448 switch which is the latest at this time.
Please note that this is a random occurrence. If I continue to unplug the network cable and plug it back in, it will eventually negotiate at 1gbps.
This is not the only problem I have found with the Dell PowerConnect 5448 switch. It also delays up to 10 seconds when passing on DHCP requests. Please see:
I believe the hardware in the Dell PowerConnect 5448 is fine... however I would avoid purchasing this switch until they release another firmware update resolving these problems.