I recently put in a new 2 TB hard drive into my mid-2010 iMac. I used the exact same brand as my old drive, and plugged in the fan temperature cable correctly. However, after using it for 15 minutes, the fan suddenly went to top speed and hasn't stopped since. I found this app, http://www.hddfancontrol.com , which I used the demo and its stopped the fan speed. However, it states on the website, "iMac HDD Fan Control does not require Apples temperature sensor or cable to obtain the drives temperature as it uses the S.M.A.R.T (Self-Monitoring, Analysis and Reporting Technology) protocol built into all drives, this means you no longer need the temperature sensor or cable for the fan to operate correctly." Is that correct that the SMART protocol can replace using the regular temp sensor? I'm worried the app is just turning the fan off. Its also $30, and I'm not sure I want to spend that much unless it is actually working and protecting my drive. Any thoughts?