Question gpu fans keep spinning at idle

[lastwood79]

my gtx 960 palit superjetstream fans used to not spinning 0 rpm at idling without any thrid party program but today i noticed my gpu fans keep spinning at idling ,the hwinfo show the fans spins constantly at 500 rpm (21%) the gpu temp is 40c , and strangely it only happen when in desktop , the fans stop spinning while in bios but spinning again after entering desktop.
what I've tried so far :
-reinstall my windows 10 (remove everything) no results
-installing new nvidia driver (clean instal) , the fans stop spinning while uninstall old driver and start spinning again after new driver installed
-reset to default using msi afterburner still no result
- reseat the gpu , no result
-nvidia control panel all setting reset to default , no result

hwinfo :

https://imgur.com/a/95EE2Ln

View: https://imgur.com/a/95EE2Ln

 

[punkncat]

In my experience, the fans on the card stop spinning in relation to the temp. Without knowing where in the world you are, is it coming into summer there? Are the case fans clean and unobstructed (dust, etc.)?
Given the age of the card it could also be in relation to needing to have the paste and pads replaced.

 

[lastwood79]

In my experience, the fans on the card stop spinning in relation to the temp. Without knowing where in the world you are, is it coming into summer there? Are the case fans clean and unobstructed (dust, etc.)?
Given the age of the card it could also be in relation to needing to have the paste and pads replaced.

the temp at idle was 40c (hwinfo) , it used to stop spinning at this temp .
fans clean and unobstructed, and i replace the paste few months ago with arctic mx4

 

[CountMike]

In my experience, the fans on the card stop spinning in relation to the temp. Without knowing where in the world you are, is it coming into summer there? Are the case fans clean and unobstructed (dust, etc.)?
Given the age of the card it could also be in relation to needing to have the paste and pads replaced.

Did you update driver perhaps ?