Controlling 3 pin fan with 4 pin spliter

[Fred_66]

My motherboard supports voltage control of fans , however it has few fan headers so what I need to ask if I can still control my 3 pin fans through my motherboard while having them connected to a 4 pin fan splitter, because I saw some posts saying that if you connect a 3 pin fan to a 4 pin fan splitter it will turn on at full speed.

 

[jakubek160]

It doesn't metter. Pluging the fan to your motherboard makes it beying controled by it. I have it plugged like that and it's all good.

 

[Paperdoc]

The Splitter is not the issue. Any 4-pin fan Splitter can be used with both 3-pin and 4-pin fans.

How the fan is controlled is set by the way the mobo header operates. The ONLY way to control a 3-pin fan's speed is by using Voltage Control Mode (aka DC Mode) at the header. The type of Splitter does not change that. NOTE that the number of pins on the mobo header does NOT tell you what you need to know. It is true that a 3-pin header can only operate in Voltage Control Mode. But many mobos today use only 4-pin fan headers. The confusion comes because the method they use for control can vary. Some use only PWM Mode (true 4-pin system design). Some use only Voltage Control Mode (ideal for 3-pin fans, but also can control 4-pin fans). Some offer you an option in BIOS Setup to set the control Mode for each header to either PWM or Voltage Control (aka DC Mode). Some claim to detect automatically which type of fan is plugged in, and make its own adjustment to use the appropriate Mode. So IF you want to control 3-pin fans, you need to determine whether the header you use can be set to Voltage Control Mode, or possibly already is set to that Mode.