Interesting article here: http://blogs.dirteam.com/blogs/tonymurray/archive/2006/08/25/Troubleshooting-LDAP-issues-with-Server-Performance-Advisor-_2800_SPA_2900_.aspx

and this one: http://blogs.technet.com/b/askds/archive/2007/08/20/troubleshooting-high-lsass-cpu-utilization-on-a-domain-controller-part-1-of-2.aspx

Article about SPA tool: http://blogs.technet.com/b/ad/archive/2007/07/08/a-day-at-the-spa.aspx