So, finally, some intense Googling found the solution to my problem of having a sluggish, laggy slow connection from a Vista machine to a Windows 2003 R2 64Bit machine. Something to do with Vista’s RDP client trying to tune something. Either case, this is the fix.
Open a command shell with admin access on the vista box, and type in
netsh interface tcp set global rss=disabled
netsh interface tcp set global autotuninglevel=disabled
I’m not quiet sure yet as to any side effects, but all i know is that this fixes my problem in trying to trouble shoot probelms quickly on clients servers that are running 64bit Win2k3