We have just dramatically upgraded our hardware for our Listserver, from a 350 mhz, 128 MB RAM, 10 GB HD WIN NT 4.0 to a 1000 mhz, 512 MB RAM, 40 GB HD, WIN2K SP2. We do several mass emails involving several huge bulk adds. On our old system it took up to 45 min to add 20,000 users to a list. The CPU would also be maxed out, average about 95% cpu time during the add. This would stall listserv performance until it was done, so the listserv was not accessible through email or the web interface for 45 minutes. Now with our new server the performance gains haven't been inspiring. It takes upwards of 30 minutes to do a 20,000 user add, disabling listerv (email and web interface). But with the new server the CPU seems to be barely used, averaging 2% cpu time. The Listserv software isn't using all the resources available on this new machine. Is there anyway to increase the performance of the Listserv. I have changed the optimization levels to the highest recommended values to no avail. How can I make sure Listserv is using greatly improved hardware resources.