If that's the case then I should upgrade my Windows 2003 Server to Vista to get that improved through-put with that new IP stack, right? Gee, I can get 30% better gig performance on my Exchange server if I read you guys correctly.
I got money on the old installation being replaced with a fresh XP wipe (*minus* all the garbage 3rd party security clients some of you like to install) running just as fast. I have several machines with dual boot Vista/XP with T-1 access if we have anybody willing to bet here.
Win2K had a theoretical 15-20% better IP efficiency over XP, but it was only realized on the transmission end. Vista pulling data down from the internet faster than XP would only indicate something wrong with the XP box.