CPU Fan Speed Problem
Printed From: ASRock.com
Category: Technical Support
Forum Name: Intel Motherboards
Forum Description: Question about ASRock Intel Motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=7470
Printed Date: 03 Aug 2025 at 12:38pm
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: CPU Fan Speed Problem
Posted By: pravin
Subject: CPU Fan Speed Problem
Date Posted: 28 Jan 2018 at 12:27am
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" rel="nofollow - AsRock B250m Pro motherboard. It has CUP_Fan 1 (4 pins) and CPU_FAN 2 (3 Pin). Intel Pentium G4560 processor stock CPU heatsink and fan. As per my knowledge, 4 Pin power connector should control the fan speed. After setting the speed at lowest in BIOS /UEFI settings using the Asrock FanStatic settings. But even after doing the settings, it still runs at full speed at all the time on CPU_Fan1 connection. So I connected it on CPU_Fan2, a 3 PIN socket. Now it runs at a lower speed as the settings as per temperature. Question is, Is the 4 Pin CUP_Fan 1 socket is not working? Is it fine to use the 3 pin socket instead of 4 pins as primary? If the fan should work as expected, what settings I need to change. I already read many forum threads here. Tried many settings. The 4 pin connector run the fan at full speed and the 3 pin connector working fine. |
Replies:
Posted By: wtuppa
Date Posted: 28 Jan 2018 at 12:46am
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" rel="nofollow - for a FAN with 3pin controls the speed is changed by changing the voltage of the FAN, a FAN with 4pin control has fixed voltage and is controlled by an additional PWM signal (on the additional pin). so if you put a 3pin FAN into a 4pin control, the FAN always runs on full speed since the voltage is fixed on 12V. so it only depends on the FAN (if it uses 3 or 4 pins). So which FAN are you using? ------------- ASRock H170 Pro4/Windows 7 |
Posted By: Abula
Date Posted: 28 Jan 2018 at 11:11pm
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You need to understand how AsRock design their headers and fan control. Usually they design what they call, autodetect headers, these are 4pin headers that can do voltage control (3pin) or PWM control (4pin), this headers will detect if you plugged a 4pin or 3pin and react accordingly, but usually asrock only includes 2 headers like this (in some cases only 1, on value mobos), the rest of the 4pin headers (that are not autodetect) are only PWM control, and most cases the 3pin headers are not controllable, like pure 12V header. One last comment, in the past the Autodetect headers were more commonly the CPU_FAN1 and CHA_FAN1 (in some mobos CPU_FAN2), recently they steered away from this practice and now on Z370 there are no autodetect headers, but switchable on bios, but the usual header that you would think as above are not switchable, for example on the Z370 Taichi only ones that can do 3pin voltage are CPU_OPT and CHA_FAN3, meaning that CPU_FAN1, CHA_FAN1 and CHA_FAN2 are pure 4pin voltage controlled. But i don't believe this is the case for your motherboard, i think yours are still when asrock did do the autodetect headers.
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Posted By: pravin
Date Posted: 29 Jan 2018 at 9:19pm
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I am using the stock Intel CPU fan. It has 4 Pins and connected to CPU_Fan 1 connector. |
Posted By: pravin
Date Posted: 29 Jan 2018 at 9:24pm
I am using the stock Intel Fan and it has 4 pins. The connection on the motherboard is also CUP_Fan1 has 4 pins. Still, it does not control the fan speed. I must mention that, when I go to BIOS, it auto-detect that I have connected the fan to it. When I change the connection to 2nd connection, it also detects that. But the 4 pin socket do not control fan speed. But the 3 Pin socked to control it. Maybe with voltage control. So, Is there any problem with the 4 pin socket? |
wtuppa wrote:Posted By: pravin
Date Posted: 29 Jan 2018 at 9:26pm
My motherboard, auto detect the fan connection. I have intel stock CPU Fan. It auto detect the connection on both headers but do not control the fan speed on 4 pin connection but do control on 3 pins. |
Posted By: Animalm4st3r
Date Posted: 30 Jan 2018 at 8:25am
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" rel="nofollow - i just pulled up your manual maybe you read it some time : 2 x CPU Fan Connectors (1 x 4-pin, 1 x 3-pin) * The CPU Fan Connector supports the CPU fan of maximum 1A (12W) fan power. ?? 2 x Chassis Fan Connectors (4-pin) (Smart Fan Speed Controll) * CHA_FAN1 and CHA_FAN2 can auto detect if 3-pin or 4-pin fan is in use. Also Try using A-Tuning Software to check your fancurves and maybe adjust them to your liking |
Posted By: pravin
Date Posted: 02 Feb 2018 at 10:04pm
I think I have already said that. Read all the manual instruction. There it clearly mentions that the cp_fan1 is 4 pins and support PWM speed. the other connector is 3 pins and auto detect. I tried using the 4 pin connector and it does not control speed. But the 3 pin connector works fine. I want to know, where is the problem. Either the fan is faulty or a socket. So that I can buy a new fan if the Intel stock fan is faulty. |
Posted By: Animalm4st3r
Date Posted: 03 Feb 2018 at 12:21am
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Okay then first check your bios make sure Fan Speed is set to Standard, if it is set to full power you can not do PWM from windows. If that does not help Try connecting it to one of the 4 pin Case Fan connectors and try if PWM works there if it does your board is faulty if not your fan is |