4 fans and only 2 motherboard headers.

Owen Goldsmith · 22 Jan 2019 at 16:04

Hey,

I have 4 fans in my PC but the motherboard only has 2 fan headers, one for the CPU fan and one for the case fan. I purchased a splitter and have connected the cpu fan, and 2 extra fans to the splitter.

However, now all 3 fans run at full speed (quite loud) and the white LED's in the 2 fans aren't on.

Any ideas why this is and what I can do to fix it?

The mobo is MSI B450M PRO-M2 and the 2 LED fans are three pin.

NMBlack · 22 Jan 2019 at 16:29

Looks like you might be trying to run voltage-regulated fans from pwm mobo headers, or you need to set a fan curve in bios?

Owen Goldsmith · 22 Jan 2019 at 16:39

NMBlack said:
Looks like you might be trying to run voltage-regulated fans from pwm mobo headers, or you need to set a fan curve in bios?

so what would you suggest I do as an alternative? I have taken a look on speedfan and the fans arent recognised individually by the motherboard.

Grandmaster Fap! · 22 Jan 2019 at 18:12

https://www.overclockers.co.uk/phanteks-pwm-fan-hub-black-ca-009-pt.html

Used one of these when fan headers are thin on the ground, works a treat with mobo control or speedfan/argus

LuckyBenski · 22 Jan 2019 at 18:15

As NMBlack says, you'll need to use DC voltage control for 3-pin fans. The Phanteks hub does a nice tidy job of converting PWM signal from motherboard headers into DC voltage variation. But it's possible your motherboard can do it already - try adjusting it in the deeper Speedfan settings.

Owen Goldsmith · 22 Jan 2019 at 18:19

Grandmaster Fap! said:
https://www.overclockers.co.uk/phanteks-pwm-fan-hub-black-ca-009-pt.html

Used one of these when fan headers are thin on the ground, works a treat with mobo control or speedfan/argus

Awesome, this looks perfect. Thanks!

Grandmaster Fap! · 22 Jan 2019 at 18:37

Owen Goldsmith said:
Awesome, this looks perfect. Thanks!

It shows you can run it with a sata cable but i just run it with it plugged in to the CPU fan header(as thats usually always pwm) and it was never a problem, more than enough power and i ran six fans from it!

doyll · 23 Jan 2019 at 20:59

If you want to be sure you won't damage your mohterboard fan header use the Sata power lead to PSU. While some fan headers can power more than 1 amp of total load many are rated 1 amp, and 4x fans rated 0.1 amp each will easily pull 0.3-0.5 amp and some up to 0.6-0.8 amp each when starting up .. so if they pull 0.3 each that is 1.2 amp total so header can handle it .. but if 4 fans are pulling 0.6 amp startup it is 2.4 amp load and that could easily damage fan header.

Owen Goldsmith · 24 Jan 2019 at 14:47

doyll said:
If you want to be sure you won't damage your mohterboard fan header use the Sata power lead to PSU. While some fan headers can power more than 1 amp of total load many are rated 1 amp, and 4x fans rated 0.1 amp each will easily pull 0.3-0.5 amp and some up to 0.6-0.8 amp each when starting up .. so if they pull 0.3 each that is 1.2 amp total so header can handle it .. but if 4 fans are pulling 0.6 amp startup it is 2.4 amp load and that could easily damage fan header.

Yeah, I have free SATA power connectors on my PSU anyway so no need to skip them.

Grandmaster Fap! said:
https://www.overclockers.co.uk/phanteks-pwm-fan-hub-black-ca-009-pt.html

Used one of these when fan headers are thin on the ground, works a treat with mobo control or speedfan/argus

I have bought and installed this however speedfan is not showing any fans except the GPU. Any ideas why this could be? The fans are powered and spinning but again not LED lit and running at 100%.

doyll · 24 Jan 2019 at 15:05

Owen Goldsmith said:
Yeah, I have free SATA power connectors on my PSU anyway so no need to skip them.

I have bought and installed this however speedfan is not showing any fans except the GPU. Any ideas why this could be? The fans are powered and spinning but again not LED lit and running at 100%.

You should have one fan on the Phanteks hub sending it's rpm signal to motherboard header it is plugged into. On my hub it's the white socket. Manual explains it all.

LuckyBenski · 24 Jan 2019 at 15:14

Owen Goldsmith said:
Yeah, I have free SATA power connectors on my PSU anyway so no need to skip them.

I have bought and installed this however speedfan is not showing any fans except the GPU. Any ideas why this could be? The fans are powered and spinning but again not LED lit and running at 100%.

You can switch settings on and off to display and/or edit fan speeds. Go through all of the config several times with a fine toothed comb... It's not always obvious what setting changes what

Owen Goldsmith · 24 Jan 2019 at 15:48

doyll said:
You should have one fan on the Phanteks hub sending it's rpm signal to motherboard header it is plugged into. On my hub it's the white socket. Manual explains it all.

LuckyBenski said:
You can switch settings on and off to display and/or edit fan speeds. Go through all of the config several times with a fine toothed comb... It's not always obvious what setting changes what

Still no luck. I have followed the manual. I have the 4 pin connector and the sata connector. Checked bios and ensured CPW header set to PWM. CPU fan is plugged into Fan 1 and the BIOS is showing the fan speed now for the CPU, but nothing showing on speedfan even when I go into configuration and advanced mode.

Grandmaster Fap! · 24 Jan 2019 at 16:05

For a test, just unplug the sata cable and run it from the cpu header. You may be unlucky and speedfan doesnt recognise the ITE chip on your mobo so cant see the fans, ive had this happen. You could download Argus monitor and see if that see's the fans.

Also do you have a bios setting for your fans like silent/normal/manual etc?

Owen Goldsmith · 24 Jan 2019 at 16:16

Grandmaster Fap! said:
For a test, just unplug the sata cable and run it from the cpu header. You may be unlucky and speedfan doesnt recognise the ITE chip on your mobo so cant see the fans, ive had this happen. You could download Argus monitor and see if that see's the fans.

Also do you have a bios setting for your fans like silent/normal/manual etc?

I'll give that a go and let you know. The only settings showing in the bios is smartfan and then the options to set at what temps the fans increase speed.

Owen Goldsmith · 24 Jan 2019 at 23:07

Downloaded Argus monitor and the CPU fan shows up so looks to be an issue with Speedfan. No LED's still but not the end of the world, I will get some separate RGB strips instead. Cheers for your help guys!

MaXxBoulton · 25 Jan 2019 at 00:15

https://www.overclockers.co.uk/akasa-ak-cb002-pwm-fan-splitter-cable-cb-031-ak.html

single best cable i ever ordered.

doyll · 25 Jan 2019 at 11:08

MaXxBoulton said:
https://www.overclockers.co.uk/akasa-ak-cb002-pwm-fan-splitter-cable-cb-031-ak.html

single best cable i ever ordered.

Akasa PWM splitter are the worst I've seen, and I used several different ones. They put too many leads into each of the power and plug connectors so if user moves wires around much they flex-stress/harden and break. So when you open up case to do something when it's closed up and started fan with broken wire doesn't run.

These are much better:
https://www.overclockers.co.uk/ek-water-blocks-ek-cable-splitter-4-fan-pwm-extended-wc-9cq-ek.html

DoneADougalOnSofa · 25 Jan 2019 at 11:22

I hate those multi-way PWM splitters! Never got mine to work. I just use these now: https://www.overclockers.co.uk/akasa-pwm-fan-splitter-ak-cbfa04-15-cb-071-ak.html

Two fans per motherboard header.
Dive into the Fan section in the BIOS, flick mode to DC (not PWM. Check first your mobo allows DC control, of course. Most do.) and run the calibration program.

That should sort you out. Speedfan is a bit hit and miss sometimes. Used to crash my old rig as soon as I clicked on it- the entire system just powered off!

Grandmaster Fap! · 25 Jan 2019 at 12:05

Owen Goldsmith said:
Downloaded Argus monitor and the CPU fan shows up so looks to be an issue with Speedfan. No LED's still but not the end of the world, I will get some separate RGB strips instead. Cheers for your help guys!

What fans are they? LED fans usually just 'work', you dont have RGB fans instead do you?

MaXxBoulton · 25 Jan 2019 at 12:08

DoneADougalOnSofa said:
multi-way PWM splitters! Never got mine to work.
Two fans per motherboard header.
Dive into the Fan section in the BIOS, flick mode to DC and run the calibration program.

the problem with the cables is a lot of motherboard even thought they say PWM control just use DC control.

DoneADougalOnSofa said:
Two fans per motherboard header.

should the first question here not be what fins dose he have and what amp's will they pull from the header, then we should see what the header can supple.
lets be clear a fan header as a single fan connection for a reason, they have a max power output and some fans will blow fan headers if you put more than one on it.