XPS 8500 Gigabit LAN SLOW!

New Dell XPS 8500 connected to Gigabit port on BT Home Hub 3.
Connection shows 1Gbps.  Accessing web sites is very slow.

Connect to 10/100 port and web access is fine.

Old Dell Vostro 220 connected at 1Gbps and worked fine !

Any ideas ?

Thanks