Gigabit NIC reports as 100m full duplex

Hi

I have a test lab with 2 identical HP Proliant 54l Microservers running ESXI 5.1. Each server is fitted with a dual port Intel 82571EB Gigabit Ethernet Controller. All the NIC's connect through a Netgear GS108E 8 port GigaBit switch. All the NIC's are set to auto-negotiate in VCenter. 

3 of the NIC's report as 1000 Full but 1 only reports as 100 Full.

I have swapped cables, ports in the switch and nothing seems to change it.  Before I installed the Intel card the On Board NIC also reported as 100 Full when it was a Gigabit NIC as well.

Any Ideas?

Alex