hi,
sure, NAV 2013 is optimized for reduce locks times (and quick resolve deadlocks if necessary)
ex: some pages are query based (readonly) instead of tables
ex: "g-l-entry table locking redesign... and Others posting routines"
blogs.msdn.com/.../g-l-entry-table-locking-redesign-in-microsoft-dynamics-nav-2013.aspx
NAV 2013 is REPETEABLE READ isolation level based, This still grants clean reads, but does not establish any Range Locks - and this will dramatically reduce blocking issues!"
on NAV 2009:
my suggestion for NAV 2009 is : change to "REPETEABLE READ" INSTEAD OF "SERIALIZABLE" isolation level; will reduce locks > no problems with phantom reads; check if you have correct release\build to activate it
look at NAV Team Blog post:
blogs.msdn.com/.../microsoft-dynamics-nav-changes-by-version.aspx
use more SQL filegroups\datafiles and move tables there, will reduce I/O times (and locks)
add memory if you have "pending" sessions on SQL Server