Hi. I have an Asrock H97 Pro4 with a i7 4790K in a Corsair Carbide 200R case. This case has two chassic fans with 3-pin cables, which I have connected to two connectors on the motherboard (chassis fan 1 and chassic fan 2, both with 4 pins). Both work, but too fast, so my computer is not silent. Under my motherboard's bios I can setup the speed of the fans. Although the adjustments work with the CPU fan, no matter that I set for the chassis fans, their speed is always the same. I have tried with Speedfan and it's the same. The only solution so far is to connect them directly to the power suply, inverting the connector, so that they receive less power. One of them works. The other one, however, refuses to start, unless I push it a little with my fingers. Any idea? I could live without the front fan, but it would be nice to have everything working. My components are good quality and I expected this to work.
I can't control chassis fan speed
- Thread starter Elaphe
- Start date
Solution
alexoiu
Titan
- Nov 1, 2012
- 39,818
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- 126,990
Hi, Not all boards can control 3 pin fans with pwm headers.
I see 2 options: using a fan controller, or 3 pin resistor cables: http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Delectronics&field-keywords=Fan%20Noise%20Speed%20Reduce
I see 2 options: using a fan controller, or 3 pin resistor cables: http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Delectronics&field-keywords=Fan%20Noise%20Speed%20Reduce
What you describe is normal. Any 3-pin fan plugged into a 4-pin port will run at full speed all the time, because what the port is doing to control fan speed does not work for 3-pin fans. You have a few options.
1. Buy 4-pin fans and install them instead. They will work.
2. Check in BIOS Setup where the chassis fans are configured. SOME mobos allow you to set the fan port to behave either as a 3-pin or as a 4-pin fan port. If you can, set these ports to 3-pin. Sometimes that is also called "Voltage Control Mode" as opposed to PWM Mode.
3. If that is not available in BIOS Setup screens, check the utilities that came on the CD with your mobo. One of them may deal with fan and cooling control, and MAYBE such a port option is in there.
4. Use alexoiu's suggestion and little resistor adapters that you place in each fan's power supply connections. This can fix the fan's speed at some lower value, but it still will not give you automatic control.
1. Buy 4-pin fans and install them instead. They will work.
2. Check in BIOS Setup where the chassis fans are configured. SOME mobos allow you to set the fan port to behave either as a 3-pin or as a 4-pin fan port. If you can, set these ports to 3-pin. Sometimes that is also called "Voltage Control Mode" as opposed to PWM Mode.
3. If that is not available in BIOS Setup screens, check the utilities that came on the CD with your mobo. One of them may deal with fan and cooling control, and MAYBE such a port option is in there.
4. Use alexoiu's suggestion and little resistor adapters that you place in each fan's power supply connections. This can fix the fan's speed at some lower value, but it still will not give you automatic control.
alsmith
Distinguished
- Oct 16, 2014
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- 0
- 18,640
You don't need to mess around with resistors- just set the UEFI BIOS properly.
It seems it will be worth sitting down and reading through the manual. Read once fairly quickly then go back and read it a bit more carefully a day or two later- it helps things go in a bit better doing it this way.
Anyhow- from the H97 Pro4 manual-
page 4
HardwareMonitor
• CPU/Chassis temperature sensing
• CPU/Chassis/Power Fan Tachometer
• CPU/Chassis Quiet Fan (Auto adjust chassis fan speed by
CPU temperature)
• CPU/Chassis Fan multi-speed control
page 80
4.6 Hardware Health Event Monitoring Screen
his section allows you to monitor the status of the hardware on your system,
including the parameters of the CPU temperature, motherboard temperature, fan
speed and voltage.
CPU Fan 1 & 2 Setting
Select a fan mode for CPU Fans 1&2, or choose Customize to set 5 CPU
temperatures and assign a respective fan speed for each temperature.
Chassis Fan 1 Setting
Select a fan mode for Chassis Fan 1, or choose Customize to set 5 CPU temperatures
and assign a respective fan speed for each temperature.
Chassis Fan 2 Setting
Select a fan mode for Chassis Fan 2, or choose Customize to set 5 CPU temperatures
and assign a respective fan speed for each temperature.
Over Temperature Protection
When Over Temperature Protection is enabled, the system automatically shuts
down when the motherboard is overheated.
It seems it will be worth sitting down and reading through the manual. Read once fairly quickly then go back and read it a bit more carefully a day or two later- it helps things go in a bit better doing it this way.
Anyhow- from the H97 Pro4 manual-
page 4
HardwareMonitor
• CPU/Chassis temperature sensing
• CPU/Chassis/Power Fan Tachometer
• CPU/Chassis Quiet Fan (Auto adjust chassis fan speed by
CPU temperature)
• CPU/Chassis Fan multi-speed control
page 80
4.6 Hardware Health Event Monitoring Screen
his section allows you to monitor the status of the hardware on your system,
including the parameters of the CPU temperature, motherboard temperature, fan
speed and voltage.
CPU Fan 1 & 2 Setting
Select a fan mode for CPU Fans 1&2, or choose Customize to set 5 CPU
temperatures and assign a respective fan speed for each temperature.
Chassis Fan 1 Setting
Select a fan mode for Chassis Fan 1, or choose Customize to set 5 CPU temperatures
and assign a respective fan speed for each temperature.
Chassis Fan 2 Setting
Select a fan mode for Chassis Fan 2, or choose Customize to set 5 CPU temperatures
and assign a respective fan speed for each temperature.
Over Temperature Protection
When Over Temperature Protection is enabled, the system automatically shuts
down when the motherboard is overheated.
What the manual describes does NOT answer OP's problem. It does indicate that you have some choices available, but does not explain what those are. There are "modes" to choose, plus a Customized option. It is common to have "modes" include Automatic (a pre-set group of parameters for automatic control based on temperature measurements), Manual (you set a speed and it stays there), Max Cool (full speed at all times) and Quiet Mode (reduced fan speeds as much as possible to reduce fan noise). But none of these are detailed in the manual, so we don't know from that what really is available. The manual also does NOT say anything about whether the 4-pin mobo port can be set instead to operate as a 3-pin port, which is really what OP needs to use his 3-pin fans.
IF those fan ports are always going to work as 4-pin ports, it does not matter what speed mode you select. ALL of them will be implemented by changing the output of the port in 4-pin mode. What does that mean?
Well, a 4-pin fan port has 4 signals. Pin #1 is Ground, Pin #2 is the +12VDC power supply, Pin #3 carries the speed pulse signal generated inside the fan motor back to the mobo for monitoring, and Pin #4 carries the PWM signal. Inside the fan motor is a small chip uses the PWM signal to modify when current from the +12VDC line actually flows through the motor. It is this last signal, PWM, that changes to alter fan speed.
On a 3-pin fan the first three pins are similar with one important difference. Pin #2 is still the +VDC supply, but this is the signal that is varied to change the motor speed. It is not always +12VDC. That is why, when you plug one of these fans into a 4-pin port where Pin #2 is ALWAYS +12 VDC the motor always runs at full speed.
So, as I suggested, OP should look at exactly what the BIOS Setup screen for those ports say. IF they offer the option to change the port to 3-pin mode or "Voltaqe Control Mode" that's the right choice, and then the other options can work. Unless that option is there, no other choices in BIOS Setup will change the problem.
IF those fan ports are always going to work as 4-pin ports, it does not matter what speed mode you select. ALL of them will be implemented by changing the output of the port in 4-pin mode. What does that mean?
Well, a 4-pin fan port has 4 signals. Pin #1 is Ground, Pin #2 is the +12VDC power supply, Pin #3 carries the speed pulse signal generated inside the fan motor back to the mobo for monitoring, and Pin #4 carries the PWM signal. Inside the fan motor is a small chip uses the PWM signal to modify when current from the +12VDC line actually flows through the motor. It is this last signal, PWM, that changes to alter fan speed.
On a 3-pin fan the first three pins are similar with one important difference. Pin #2 is still the +VDC supply, but this is the signal that is varied to change the motor speed. It is not always +12VDC. That is why, when you plug one of these fans into a 4-pin port where Pin #2 is ALWAYS +12 VDC the motor always runs at full speed.
So, as I suggested, OP should look at exactly what the BIOS Setup screen for those ports say. IF they offer the option to change the port to 3-pin mode or "Voltaqe Control Mode" that's the right choice, and then the other options can work. Unless that option is there, no other choices in BIOS Setup will change the problem.
alsmith
Distinguished
- Oct 16, 2014
- 76
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- 18,640
I think it does- *if* you read it properly, follow the manual *and* know what you are doing (by reading it properly- which is why I said read it twice to the OPP. ymmv but you may need to try reading and understanding the question and manual another 2 or 3 times. Good luck.) .
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