Originally Posted by Fumz
I am sure this is a simple home network with a DSL/Cable router with a built-in switch. So the data transfer between machines is not limited by the router since the switch is more capable than the systems.
Originally Posted by bpfeil
What speeds are the Ethernet interfaces used by each system?
The router you have supports up to 1 Gigabit. If the XP system has a lower bandwidth interface than the Vista systems, it would not be surprising to see a big speed difference.