Question Undervolt case fan issue

[Spysoaa]

Hi!
I have an undervolting issue with one of my pc case fans, when i undervolt from 12 to 7V, it works fine but when i undervolt it to 5V, it starts then stops then starts repeatedly in a cycle equal intervals apart (about 4-5 seconds). I have another same fan in the case and it runs without any problems on 5V.
Please any help would be highly appreciated
Thanks!

 

[kerberos_20]

replace fan with PWM will resolve your issue

 

[CountMike]

Hi!
I have an undervolting issue with one of my pc case fans, when i undervolt from 12 to 7V, it works fine but when i undervolt it to 5V, it starts then stops then starts repeatedly in a cycle equal intervals apart (about 4-5 seconds). I have another same fan in the case and it runs without any problems on 5V.
Please any help would be highly appreciated
Thanks!

Different fans have different startup voltages and speeds, can't put them all in same "bag" and expect them to behave sane way. How are you undervotling them and what are they connected to ?
Are you using method of switching contacts on Molex or using resistors ?