Review on 🔌 ThreeBulls 2 Pack PWM Fan Splitter Cable, Sleeved Braided Adapter for Computer PC Fan Power Extension, 1 to 3 Converter for ATX Case Cooling Fan Cable, 10.6" 4-Pin/3-Pin by Tyler Dorsey

As described these expanders work equally well with 3 and 4 pin fans. The 4-pin socket connects to a 3-pin or 4-pin socket on the motherboard. It is divided into three connector cables to which the fans are connected. Only one of the three has four wires going to four pins, the other two only have three pins and three wires. Wait! The? How can it work? Here is the answer. One pin, pin 3, is for the fan tachometer. This is true regardless of whether you are using a 3 or 4 pin fan. The RPM signal tells the fan controller how fast the fan is spinning. If all 3 headers had this pin there would be a conflict when all 3 fans try to report their respective fan speeds over the same connection. So if you disconnect the fan connectors this way, only one fan will report its RPM. If you want all connected fans to report their speed individually, they must be connected to different fan headers on your motherboard. Make sure at least one fan is connected with all four pins on the connector to get the tach signal. . If you don't connect a fan to the 4-pin connector, the other two fans will always run at maximum speed because there is no tach signal. When connecting fans to a splitter, it is recommended to ensure that they are all the same. models because the fan controller has no idea that it regulates the speed of multiple fans with different characteristics. The cables themselves seem good enough, but I deducted 1 star for not having a wiring guide with that information.