Iam experiencing the same problem. VPN (using OpenVPN) is very slow compared to WinXP. I also disabled Remote Differential Compression
but it did not affect the speed in anyway(atleast noticeable). I use VPN mainly when I code using Netbeans and initializing project takes forever. I have mapped network drive of our project server. For example changing directories is very sluggish compared what it used to be with WinXP.
Oh yeah, I also tried disabling IPv6 as I read somewhere that it also could affect the speed but no difference(and it feels silly that I have to disable IPv6 for speedup).
I didnt try the command prompt yet but will do when I get back home.
I hope there is a solution to this as I really like Win 7(just switched to it couple of weeks ago)..