RPM speed monitoring on 3pin 3way non PWM fan splitter cable

donfm

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I have a Gigabyte Z170X Gaming 7 rev 1.0 MoBo. I want to add a 3 way fan splitter cable to run 3 identical non-PWM case fans off the same Sys_Fan header which is not PWM.

Now in order to monitor the RPM of the fans through BIOS my understanding is that this cable can have only one RPM sensing wire back to the motherboard header. This should give me the speed of all the identical fans based on the speed of one fan.

I have been looking at 3 and 4 way 3pin splitter cables until I am blue in the face trying to find one with only one "sense wire" connection on only one of the 3 fan connectors. Do they make such and animal? Would it be possible to simply cut 2 of the sense wires on the 3-fan connectors making it do what I want? Would a any 4 pin cable be able to do this?

I am unclear if the MoBo fan speed control uses the case ambient temp to control the fans by outputting a percentage of voltage to the fans

I have not been able to find in the MoBo manual the maximum output amperage for the Sys_Fan header. Most people suggest it is typically 1 amp DC..
 
Yes, you can simply cut two of the three sensing wires.

As to how many fans can be connected, that depends on the power draw of the fans and the capability of the motherboard header.

Look at the fans themselves, the amp draw should be on the label. 0.3 might be typical for a normal 120mm fan.

If the cpu fan header capability is 1 amp, then you could attach 2 or 3 such fans.

Why do you need to use splitters?
You have 3 available fan headers in addition to the cpu header so you can attach the fans singly.
 

donfm

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The 3 sys_fan non PWM headers are already in use as well as the CPU header. My mobo only has .5 amp DC rating. The 2-140MM non PWM 3 pin fans are rated at .18 amp so two would be .36 amp on a .5 amp fan header. Gigabyte support advised me NOT to use a splitter cable.