This brought to our attention on Google+: https://plus.google.com/b/114598373874764163668/116726439814896173562/posts/b9ydzhxmZKs
If I understand correctly, the contents of the roaming profile are copied to the local machine at login time, and then copied back to the server at logout time. So if we are storing unnecessary data in the roaming profile this will perform poorly in scenarios like this. -Rob
