Showing results for 
Search instead for 
Did you mean: 

Fan acts different PWM vs Duty Cycle

Level 8

I run the bios fan control and have tried in both situations to run optimize All or whatever it is.  Motherboard is x670e-e gaming.  Fans are:

Here's the deal.  If I run optimize for PWM mode I can get it down to 36%?  That's about 3k RPM.  Before running optimize i  could set it to 0% and would spin at 3k RPM, not stop 

If I run optimize for DC mode I can get it down to maybe 9%? and is running super slow like 800RPM?  Maybe less?  Set it to lower or 0 it stops spinning.

Lots of articles say you should run your fans in PWM mode if they are 4 pin but not sure I want my fans running 3k RPM if they don't need to.  Not super loud but I will have 8 of these.  Noise aside, curious what's happening here.  In my mind DC mode is what I would technically want as I have full control of the fan speed lows and highs.  So anyone know why this is happening and what I should do?

Also because of the number of fans and wattage will need to run these off a fan hub with a SATA power connector and a 4 pin cable from the hub to one of the MB fan headers.  Will that work in DC or PWM mode or automatically work in one or the other being a hub vs each fan directly connected to the MB?