Windows Explorer extremely slow to load specific network folders

Hello,

We have a Windows Server 2003 domain environment with a NetApp FAS2020 SAN.

When we are on our client machines (XP SP3) or server machines (2003 R2) and
browse to specific folders on a share of the FAS2020, the folder can take
10-20 minutes or more to open. Sometimes it opens instantly, other times it
locks up as described above.

This happens whether the folders are accessed via mapped drive or UNC
sharename (\\servername\folder1\folder2).

We have done some packet captures while this is happening, and we see
filenames and abridged contents of what appears to be all files in the
subdirectories below.

NetApp is clueless on the issue and blames it on Windows.

Due to the traffic we are seeing on the wire, I also suspect that it may be
a Windows issue. Windows seems to be querying for every filename and some of
each file's contents.

However, we previously had the same directory structure on a Server 2003 NAS
machine and this was never an issue.

We have ruled out our AntiVirus product as the cause (Symantec Endpoint
Protection 11) due to this being an issue on unprotected machines as well.

The folder structure is large (154,000 files, 13,000 folders). A workaround
might be to break this up into different root level folders, but I feel that
that shouldn't be neccessary (especially as this has worked in the past).

Any ideas or comments?

Thanks!