Hi Julxu,
The CSS operates by sharing the resources (distributed architecture) through the different modules. Please clarify a few things:
You are seeing only the SAM reaching 100%? or the SCM would also spike?
At high CPU times, do you see performance issues? drops? slowness?
How often is the issue happening?
The CSS will tipically spike CPU due to 1 of these reasons:
-Too many scripted keepalives
-DOS attacks
-SNMP Polling
It is not so complicated to identify the reason for the spike by running an spy report, however this is something that needs to be reviewied with applied with TAC help. I would not recommed adding another SAM (or IOM) until you rule out the high CPU problem.