Check the notification server cache file:
..\CA\DSM\appdata\cfnotsrvd.dat
This file grows with every DSM Explorer connection, and decreases when DSM Explorer gracefully closes.
The problem is when DSM Explorer does not gracefully close-- it leaves notification subscribers in the cfnotsrvd.dat file, which will cause the DM to push notification messages via CAM messaging, to the remote IP. If the remote IP is not online/available/responding via CAM, it will cause messages to pile up on CAM on the DM, which will result in an overall application performance issue.
If the file is >50kb, I recommend stopping CAF, deleting the file, and restarting CAF. This will clear the slate, and perhaps resolve your performance issue.
Performance issues typically require troubleshooting, so I do recommend you log a case with Support. The above suggestion is common enough, so I figure worthwhile to check.