[SOLVED] How to make a CASE FAN PWM work if CPU_FAN is being used

Oct 16, 2021
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Sorry my english sucks,
I have a basic motherboard, MSI H310M PRO M2 PLUS, I use it with an i3 9100F and a 1650, I decided to improve the temperature of my pc to be able to demand it to the maximum, that included changing thermal compound and a new heatsink, the question is that now I want to change The stock cooler that my DEEPCOOL MATREXX 30 case has, for a better one, in this case an ARCTIC P12 PWM PST ARGB, the price was good so I bought it. The problem comes when I realize that my board only has a CPU_FAN connector, THAT IS ALREADY CONNECTED with the processor heatsink, and ONLY ONE SYS_FAN. the case stock is connected via molex by the source

Is there a way to get the arctic's PWM to work? I understand that if you use the molex from the power SUPPLY or use the SYS_FAN on the board, it will not have automatic temperature "detection" so it will always go at the same RPM. I would sacrifice the ARGB but I prefer the automatic regulation function.



ARCTIC CONECTORS : https://pixeldrain.com/l/G6SxYGXZ#item=0

MOTHERBOARD : https://pixeldrain.com/l/G6SxYGXZ#item=1
 

Paperdoc

Champion
Ambassador
Your understanding of the fan headers is not quite right. You have two headers. One is the CPU_FAN header, and you have the CPU cooler plugged in there. Leave that alone. The other is a SYS_FAN header intended for any case ventilation fan(s). In ideal circumstances you would connect all of your case fans to this header, which would require something like a Splitter. BUT you have already a case vent fan connected to the PSU by Molex. I strongly suspect that this one is a THREE-pin fan, and that can NOT be speed-controlled by the PWM system. So, leave it alone, too. For your new Arctic PWM-type 4-pin fan, DO plug that into the mobo SYS_FAN header. This header CAN be set to control the speed of that PWM fan according to an actual temperature measured by a sensor on the mobo. See your manual, p. 16 for how to enter BIOS Setup. Unfortunately, the manual does NOT show us any detail on what the several screens look like, so we'll have to guess. In most of these, there will be a screen where you can examine and configure the details of how the fan headers operate. Look for that, and select the SYS_FAN header to adjust. It may already be set up correctly by default, but check. It should be using the default "Standard" or "Normal" strategy for automatic control, and be set to use PWM Mode, and not DC or Voltage Mode. IF there is a choice offered about which temperature sensor to use for this SYS_FAN header, choose the one on the mobo, not the one inside the CPU. IF you have to change any setting, be sure to use the F10 key that will pop up a window asking for confirmation that you want to SAVE and RESET, then do that. Your system will reboot with the new setting.
 

Aeacus

Glorious
Ambassador
ARCTIC P12 PWM PST
The PST in the name means that you can connect another fan to the Arctic fan, for PWM pass-through.

To solve your issue:
  1. Connect Arctic fan directly to CPU_FAN header
  2. Connect CPU cooler fan to the PST port, on Arctic fan power cable
This way, both fans have PWM and work in sync, by powered from CPU_FAN header.

automatic temperature "detection"
In Arctic Cooling lineup, there is a fan that comes with temperature probe, so fan adjust the speed according to the probe. To identify it, there's TC in the fan name,
specs: https://www.arctic.de/en/P12-TC/ACFAN00176A

use the SYS_FAN on the board
Difference of CPU_FAN and SYS_FAN, for the most part, is that CPU_FAN spins according to the CPU temperature and you may not be able to set a custom fan curve to it. SYS_FAN header is used for case fans and that header usually has customization options, that you can do within BIOS. Btw, your SYS_FAN header is also 4-pin with PWM control. So, you can connect your Arcitc fan there as well. This way, you can have independent control over it.
 

Paperdoc

Champion
Ambassador
Your understanding of the fan headers is not quite right. You have two headers. One is the CPU_FAN header, and you have the CPU cooler plugged in there. Leave that alone. The other is a SYS_FAN header intended for any case ventilation fan(s). In ideal circumstances you would connect all of your case fans to this header, which would require something like a Splitter. BUT you have already a case vent fan connected to the PSU by Molex. I strongly suspect that this one is a THREE-pin fan, and that can NOT be speed-controlled by the PWM system. So, leave it alone, too. For your new Arctic PWM-type 4-pin fan, DO plug that into the mobo SYS_FAN header. This header CAN be set to control the speed of that PWM fan according to an actual temperature measured by a sensor on the mobo. See your manual, p. 16 for how to enter BIOS Setup. Unfortunately, the manual does NOT show us any detail on what the several screens look like, so we'll have to guess. In most of these, there will be a screen where you can examine and configure the details of how the fan headers operate. Look for that, and select the SYS_FAN header to adjust. It may already be set up correctly by default, but check. It should be using the default "Standard" or "Normal" strategy for automatic control, and be set to use PWM Mode, and not DC or Voltage Mode. IF there is a choice offered about which temperature sensor to use for this SYS_FAN header, choose the one on the mobo, not the one inside the CPU. IF you have to change any setting, be sure to use the F10 key that will pop up a window asking for confirmation that you want to SAVE and RESET, then do that. Your system will reboot with the new setting.
 
Oct 16, 2021
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1
15
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Thanks, I was able to activate the PWM mode, and find the Smart fan function in the MSI BIOS. Now I just need to buy an Argb controller and that's it.
 

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