Nvidia 840m temp not monitored properly

[GregZ]

Hey guys,

I am new to GPU-Z software, so perhaps there is a simple explanation. My Lenovo laptop is running on Intel Graphics and Nvidia 840m. When I try to monitor the temp of the Nvidia card, I get 0 C and then merely glimpses of the real temperature and clock speed (see attached thumbnails). Has anyone experienced this? What is causing this?

Thanks for your responses!
GregZ

 

[StefanM]

I have a similar rig. It's caused by NVIDIA's Optimus technology. The GeForce GPU periodically turns off to save energy when idle.
If you open the render test window to keep the GPU busy and then switch to sensor tab everything looks normal.