Interesting.
I see virtually no difference in CPU temps with Sensor Panel active and with rig at idle (only default Windows applications running).
I see an increase in CPU usage for AIDA64 from fluctuating between .01% and .78% with AIDA64 running without Sensor Panel active, to between .01% and 1.94% with Sensor Panel active.
This is with Update Frequency for Sensor page, Sensor icons, and SensorPanel all set to 100ms.
Not sure if there is any setting other than Update Frequency that would cause higher CPU usage, which generally is what causes higher temps.