I am a noob when it comes to troubleshooting SnowLeopard. On a freshly booted OS .. Activity Monitor shows 1-2% CPU usage. After letting it idle for several minutes ... the CPU spikes to about 30% and never comes down below 30%. When this happens I cannot even log out (Though I am able to log out fine before the CPU spikes up). Here is the interesting thing ... when the CPU is at 30% ... the Activity Monitor shows no significant activity by any specific process. All listed processes are either 0% or 1-2%. What diagnostic tests can I perform to see what is causing this CPU spike? I have the very latest software update installed.