Diagnose periodic slowdowns/freezes
Sometimes a good place to look is the syslog.  If you know it's every 10 seconds then there's a chance that a message will get logged for whatever is happening.  Try this in terminal and append the results to your question or even have a look yourself for anything that looks unusual which is happening on 10 second intervals.

tail -n 20 /var/log/system.log  

You need to be an admin user to run the above command