Since a few days my IMac started showing weird behaviour. In Activity Monitor it shows that my CPU is 100% used. Literally 0% idle, but there are no Applications using anywhere near this much resources. The highest percentage would be from Activity Monitor itself, but this just uses 2.5% at max. The amount of CPU used is shared over 'User' and 'System' they both use around 50% CPU at the same time.
Also, the amount of threads running is around 300 to 375, but the sum of all running applications their threads doesn't go over 100.
My question is: Is there any explanation for this behaviour? And can I do something against this?
Info about my Mac:
OS : Mac OS X 10.7.5
CPU : 3.06 GHz Intel Core 2 Duo
Memory : 4 GB 1067 MHz RAM
(iMac Late 2009)
After making sure that I was looking at 'All Processes' that are running on my iMac, I found that Norton Deepsight was causing a big part of my issue. By changing a setting in my Norton-AntiVirus I managed to take atleast 50% of CPU usage away. Yet my System is still using around 50% to 60% of CPU, which is caused by 'kernel_task' and 'SymDaemon'
Is there a clear reason to why these to processes are using this much CPU?