Certain computers were reported to periodically hit 90-100% CPU utilization for as many as 15 minutes at times during the day. The spikes were not always reported on the same computers. However, a clue was that, whenever AeXNSAgent.exe was using a high percentage of the CPU the process STPatchAssessmentSrv.exe was usually using the second highest percenage. Sometimes it was using the most.
The number of clients reporting to the SMP was 18,000+. The Windows Patch Assessment Scan program was being run every four hours (default). Queries to the database seemed to indicate that all of the computers were running the program in the relatively same time frame. Which was causing contention in the app pools when posting the result to the NS>
Randomizing the run of the assessment scan program had a positive impact. This was accomplished by making three cloned copies of the "Windows System Assessment Scan" policy then targeting 1/4 of the computers in their environment. Repeat dividing up the other 3/4 of the computers among the remaining policies and setting those policies to run at different times the next day.