I finally figured out the root cause of this problem..  I have a SonicWall running SonicOS 3.1 which doesn't support RFC 1323 (Scaled TCP Windows).  When I turn off Strict Stateful Packet  Inspection on the SonicWall, the Vista auto-tuning can be turned on in Vista and the network is very fast.

So anways.. not a problem in Vista.  SonciWall's suck...  can't upgrade to newer code without rebuilding the configs, which isn't an option.