Oddball fix for slow network and Internet response under Vista

I too am having problems integrating two new identical Vista machines into
my home network. All the XP machines run fine.

The two machines connect, but performance is ISDN speeds versus cable - one
hundreth of the anticipated speed of 6 Mbs.

I've searched and found over 30 remedies and have started on some of them
(turning off Statefull Packet Inspection and Autotune, install all upgrades,
etc etc etc - life should be simplier with this).

However, I've accidentally found a surefire fix: Plug an old hub between the
PC and the router. Speeds are instantly restored. Nothing else works.

This hub as Auto-Negotiation and I'm wondering if that somehow fixes Windows
Scaling or some of the other "improvements" that have made this a miserable
experience.

Any ideas? Somebody want to confirm the hub trick?

Regards,

Michael