Browsing issue- Workgroup Network

I presently run a small 12 user workgroup running Autocad.
I presently use a Windows 2000 workstation as the
workgroup server. When I browse to a directory share with
5 gig worth of files and no directories it takes 2
minutes to open. I mapped a drive but the more files
within a directory the longer it takes to open. I open a
directory with subdirectories or less files it takes much
less time. Will the server version improve this latency
issue? Is there anything I can do to improve the
performance on the present system? I know they can
recreate the directory structure and that would certainly
improve network performance. The workstation acting as
the file server is a 2.0 gig machine with plenty of space
and ram. Why does browsing to a directory with a large
number of large files take so long to open? Anything I
can do on the workstation to improve performance would be
helpful. Any ideas!!!

Thanks

Tom