But yea since vista has a "learning" stack like on linux and OS X you can't really tweak it like on XP. You can just about only change the TCP receive window and send window.
Unless a new Cablenut version has been made for Vista the TCP receive window and send window CN makes are in the registry location they are in XP.They are there but don't change the Vista TCP receive window and send window.
Using netsh int tcp set global commands are the only way to change the TCP receive window and send window at all.Even then you don't have real control in that you can set the size.
I don't know how to set the send but my receive is currently 65340 .I have disabled it with netsh int tcp set global commands .I played around with these settings & it may have been using "experimental" setting then back to disabled that even set Vista to this.
Do you know where I can check the Vista send window?