So has anyone seen this before?

I've got 2 Windows 2008 R2 servers, one web, one file sitting in a customer's domain.

On the web server I can copy a file from the file server to the web server , using the command prompt so I can specify the user account with runas,  If I use a particular account - oh, lets say its the web service account :| - then the speed of the copy is somehow limited to 600kB/s.

Using the same command with any number of other user accounts (and a different file to avoid caching) I get a full 100MB/s.


Mapping the share on the file server to the web server seems to give me a workaround for now, but I'd love some troubleshooting ideas if anyone's got some.   All of the accounts (including the web service account) are domain accounts.

*scratches head*