[SOLVED] Control 3 pin? 3-pin vs Molex?

Svalkash

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Dec 10, 2019
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Hello everyone. I need your advice about fans.
Already bought a motherboard ASRock Fatality B450 gaming K4 and Midi-tower case with 4 vents.
The problem is that all vents have 3-pin and Molex ports.
Mobo has 3 ports for 4-pin vents, power supply - 2 Molex.
  1. Recently heard that some motherboards can control 3-pin vents too. How to understand if my mobo supports that feature?
  2. What is better: 3-pin (if can't control) or Molex?
  3. I can connect all 4 vents "through" each other. Is it good or not?
 
Solution
I suggest you do NOT connect those four case vent fans to the Molex output from your PSU. But the fact that they each have both a 3-pin fan connector and a pair (male and famale) of Molex connectors on their wires offers a useful arrangement. You can use the Molex connectors to connect a pair of fans together as if you had a fan Splitter.

You have 4 vent fans, and 3 mobo CHA_FANn headers. See your mobo manual, p. 73. It shows you CAN have the mobo do automatic speed control of the fans if you set its configuration correctly. So, connect three fans each to one of thse CHA_FAN headers using the smaller fan connector. When you do, the fourth pin of each header simply will not be used. For the fourth fan, just plug its male Molex (with...
I suggest you do NOT connect those four case vent fans to the Molex output from your PSU. But the fact that they each have both a 3-pin fan connector and a pair (male and famale) of Molex connectors on their wires offers a useful arrangement. You can use the Molex connectors to connect a pair of fans together as if you had a fan Splitter.

You have 4 vent fans, and 3 mobo CHA_FANn headers. See your mobo manual, p. 73. It shows you CAN have the mobo do automatic speed control of the fans if you set its configuration correctly. So, connect three fans each to one of thse CHA_FAN headers using the smaller fan connector. When you do, the fourth pin of each header simply will not be used. For the fourth fan, just plug its male Molex (with pins) into the female (with holes) of one of the other fans. This will put those two fans connected in parallel to a single header, just as if you had used a fan Splitter. Do NOT connect any Molex to a Molex output from the PSU.

Now to configuration in BIOS Setup (p. 73). Make these settings for each CHA_FAN header separately in order, this way:
CHA_FANn / WP Switch to Chassis Fan, not pump
CHA_FANn Control Mode to DC Mode for your 3-pin fans, not PWM Mode
CHA_FANn setting to Standard Mode so it does normal automatic control
CHA_FANn Temp Source to the motherboard temp sensor, not the one inside the CPU chip

When you have set these for all three headers, use the Esc key to return to the main menu (p. 58) and click on Exit at top right. See. p. 78, and there choose Save Changes and Exit to save your settings and reboot.
 
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Solution
I suggest you do NOT connect those four case vent fans to the Molex output from your PSU. But the fact that they each have both a 3-pin fan connector and a pair (male and famale) of Molex connectors on their wires offers a useful arrangement. You can use the Molex connectors to connect a pair of fans together as if you had a fan Splitter.

You have 4 vent fans, and 3 mobo CHA_FANn headers. See your mobo manual, p. 73. It shows you CAN have the mobo do automatic speed control of the fans if you set its configuration correctly. So, connect three fans each to one of thse CHA_FAN headers using the smaller fan connector. When you do, the fourth pin of each header simply will not be used. For the fourth fan, just plug its male Molex (with pins) into the female (with holes) of one of the other fans. This will put those two fans connected in parallel to a single header, just as if you had used a fan Splitter. Do NOT connect any Molex to a Molex output from the PSU.

Now to configuration in BIOS Setup (p. 73). Make these settings for each CHA_FAN header separately in order, this way:
CHA_FANn / WP Switch to Chassis Fan, not pump
CHA_FANn Control Mode to DC Mode for your 3-pin fans, not PWM Mode
CHA_FANn setting to Standard Mode so it does normal automatic control
CHA_FANn Temp Source to the motherboard temp sensor, not the one inside the CPU chip

When you have set these for all three headers, use the Esc key to return to the main menu (p. 58) and click on Exit at top right. See. p. 78, and there choose Save Changes and Exit to save your settings and reboot.
... Wow. I didn't think that's possible.
It seems I've read the wrong manual. Thank you.