Windows 7 ICS high latency on client PC

First off I would like to say that this worked fine under Vista.

When the main PC has ICS enabled then this causes the client PC to expirence significantly elevated pings in games that use a dedicated server.

For example if in a match of tf2 the windows 7 pc may have 70 ping to the server and the client pc may get 130ping, even though the line is obviously capable of 70ms.

Under Vista the client pc would almost always get the same ping or somehow lower than the machine giving the internet.

This makes no sense, any advice to make the ICS under 7 treat both pcs equally?