MS SQL, ADO & Delphi 5

Is there a formula or could someone share with me any insights on the
resources required by a Server and its workstations when running a Delphi
app using ADO.  This app is pushing between 4000-6000 records while updating
3 or 4 support files (counters and statistical fields).  It's running
anywhere from 6-15 user (tyically 12+).  It's experiencing server timeouts
on transactions which get progressively worse as users increase until no one
can effective produce work.

Any help, guidance or reference source would be most appreciated.

Thanks

Ted