Question Do fans with no pwm need to be connected to the motherboard?

Andrea Burgio

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I just bought these fans https://www.amazon.com/ARCTIC-Standard-Cooler-Configuration-Possible/dp/B076BXLHWC i would like to know if i need to plug them in the motherboard even though you cant control them and they always run at the same speed. I have one (different model and old) that doesnt use pmw as well and it just needs to be connected to the power supply. Can you guys help me out? I need to know it because i have to check if i need to buy a splitter for the pins of the motherboard or not
 

SteveRX4

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You can still control their speed with motherboard bios or software. They are 3 pin fans - that fit 4 pin headers.
4pin gives you better control and efficiency.

 
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You should still connect them to your motherboard.

Even though they're 3 pin on modern motherboards they'll be DC voltage controlled as opposed to PWM. That basically means that your motherboard will control how much voltage it sends to the fan determining its speed.

Connecting them to the motherboard is still worth it, as they'll still be controlled as opposed to running at full blast continuously from the PSU.
I had some Arctic 120 mm case fans and when they got to max RPM they were annoyingly loud.
 

Andrea Burgio

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You should still connect them to your motherboard.

Even though they're 3 pin on modern motherboards they'll be DC voltage controlled as opposed to PWM. That basically means that your motherboard will control how much voltage it sends to the fan determining its speed.

Connecting them to the motherboard is still worth it, as they'll still be controlled as opposed to running at full blast continuously from the PSU.
I had some Arctic 120 mm case fans and when they got to max RPM they were annoyingly loud.
Ooh i didnt know it, thank you! Can i ask you something though, i have this motherboard:
https://www.msi.com/Motherboard/B550-A-PRO
I dont know if it supports all 5 fans at the same time or i have to buy a splitter/hub or whatever its called, can you help me out please? I cant really figure it out
 
Ooh i didnt know it, thank you! Can i ask you something though, i have this motherboard:
https://www.msi.com/Motherboard/B550-A-PRO
I dont know if it supports all 5 fans at the same time or i have to buy a splitter/hub or whatever its called, can you help me out please? I cant really figure it out
That website is so bad. Seriously... tried to get the manual for the motherboard, I couldn't. I'm on my phone right now and that website is unusable for mobile. MSI needs to really work on that... just horrible UI.

Getting that out of the way, look on your motherboard for the headers with SYS_FAN printed near them... on their specifications they claim having 6 case fan headers... so it should be enough:

INTERNAL CONNECTORS
  • 1x 24-pin ATX main power connector
  • 1x 8-pin ATX 12V power connector
  • 6x SATA 6Gb/s connectors
  • 2x M.2 slots (M-Key)
  • 1x USB 3.2 Gen 1 5Gbps Type-C port
  • 1x USB 3.2 Gen 1 5Gbps connector (supports additional 2 USB 3.2 Gen 1 5Gbps ports)
  • 2x USB 2.0 connectors (supports additional 4 USB 2.0 ports)
  • 1x 4-pin CPU fan connector
  • 1x 4-pin water-pump fan connector
  • 6x 4-pin system fan connectors
  • 1x Front panel audio connector
  • 2x System panel connectors
  • 1x Chassis Intrusion connector
  • 1x 4-pin RGB LED connector
  • 2x 3-pin RAINBOW LED connectors
  • 1xTPM module connector
  • 1x Clear CMOS jumper
https://www.msi.com/Motherboard/B550-A-PRO/Specification
 

Andrea Burgio

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That website is so bad. Seriously... tried to get the manual for the motherboard, I couldn't. I'm on my phone right now and that website is unusable for mobile. MSI needs to really work on that... just horrible UI.

Getting that out of the way, look on your motherboard for the headers with SYS_FAN printed near them... on their specifications they claim having 6 case fan headers... so it should be enough:

INTERNAL CONNECTORS
  • 1x 24-pin ATX main power connector
  • 1x 8-pin ATX 12V power connector
  • 6x SATA 6Gb/s connectors
  • 2x M.2 slots (M-Key)
  • 1x USB 3.2 Gen 1 5Gbps Type-C port
  • 1x USB 3.2 Gen 1 5Gbps connector (supports additional 2 USB 3.2 Gen 1 5Gbps ports)
  • 2x USB 2.0 connectors (supports additional 4 USB 2.0 ports)
  • 1x 4-pin CPU fan connector
  • 1x 4-pin water-pump fan connector
  • 6x 4-pin system fan connectors
  • 1x Front panel audio connector
  • 2x System panel connectors
  • 1x Chassis Intrusion connector
  • 1x 4-pin RGB LED connector
  • 2x 3-pin RAINBOW LED connectors
  • 1xTPM module connector
  • 1x Clear CMOS jumper
https://www.msi.com/Motherboard/B550-A-PRO/Specification
Oh i didn't notice it, thank you!!
 

Andrea Burgio

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May 6, 2015
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You should still connect them to your motherboard.

Even though they're 3 pin on modern motherboards they'll be DC voltage controlled as opposed to PWM. That basically means that your motherboard will control how much voltage it sends to the fan determining its speed.

Connecting them to the motherboard is still worth it, as they'll still be controlled as opposed to running at full blast continuously from the PSU.
I had some Arctic 120 mm case fans and when they got to max RPM they were annoyingly loud.
Can i ask you one more thing (im sorry but im a little worried) i bought this case (still dont have though) https://www.thermaltakeusa.com/h200-tg-rgb-2.html#additional
And it says "CPU cooler height limitation: 180mm" they mean the height of the tower coolers right? So if i buy this cooler: https://www.deepcool.com/product/cpucooler/2019-11/7_12726.shtml it should work out just fine right? Since its 157.5mm, correct?
 
Can i ask you one more thing (im sorry but im a little worried) i bought this case (still dont have though) https://www.thermaltakeusa.com/h200-tg-rgb-2.html#additional
And it says "CPU cooler height limitation: 180mm" they mean the height of the tower coolers right? So if i buy this cooler: https://www.deepcool.com/product/cpucooler/2019-11/7_12726.shtml it should work out just fine right? Since its 157.5mm, correct?
Yes, they specify the height of the CPU cooler... doesn't matter if it's a tower or a down draft cooler (the type similar to the amd/intel stock cooler).

That cooler will fit easily in your case... the case has a lot of room for basically any cooler height wise.
 
Last edited:

Paperdoc

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In BIOS Setup for each of the six mobo SYS_FAN headers you should find that there is an option for the control MODE, which is the method by which the header will contrlo the fan speed. Options normally include these days: PWM Mode, Voltage Control Mode (aka DC Mode or Voltage Mode), or Auto. Set them all to Voltage (aka DC) Mode for your 3-pin fans.
 
Last edited:

lordmogul

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You can plug them into any of the 4-pin PWM or 3-pin DC fan headers. Check your motherboard which fan headers support voltage mode. (Not all motherboards support it on all ports, so double check to be sure)
And if you're really desperate you could even wire them directly to the PSU. They would run at a fixed speed (depending on the voltage provided 5V, 7V or 12V) but will run.
 

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