you can use perfmon.
Do you have SNMP enabled on the systems? Is WMI queries or WMI SNMP an option?
http://microsoft-engineer.com/index2.htmlhttp://social.technet.microsoft.com/Forums/en/winserverNIS/thread/6d460399-9bdb-4f34-b08f-892942e87b26As far as settomg thresholds, see what the normal range is for your system. What applications/services does/do the system/s provide?