W2K8R2: Filecopy over network slow

Problem: File copy on a Windows Server 2008 R2 x64 from a Windows Server 2003 R2 x64 network share is very slow.

Solution (in my environment): Fire the following command as an administrator and reboot the server:

netsh interface tcp set global autotuninglevel=disabled

On a german OS this leads to the following state:
Before:

After:

For further reading: Link

Now file copy over network is kind fun again… :-)