4 fans and only 2 motherboard headers.

Associate
Joined
17 Jan 2019
Posts
17
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.
 
Soldato
Joined
28 Dec 2017
Posts
8,385
Location
Beds
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.
 
Soldato
Joined
1 Jul 2011
Posts
8,632
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.
 
Associate
OP
Joined
17 Jan 2019
Posts
17
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.

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%.
 
Soldato
Joined
1 Jul 2011
Posts
8,632
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.
 
Soldato
Joined
28 Dec 2017
Posts
8,385
Location
Beds
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
 
Associate
OP
Joined
17 Jan 2019
Posts
17
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.
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.
 
Joined
10 Jan 2004
Posts
9,831
Location
Poland
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?
 
Associate
OP
Joined
17 Jan 2019
Posts
17
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.
 
Associate
OP
Joined
17 Jan 2019
Posts
17
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!
 
Soldato
Joined
1 Jul 2011
Posts
8,632
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
 
Associate
Joined
3 Feb 2012
Posts
2,267
Location
Bath
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!
 
Permabanned
Joined
11 Jan 2019
Posts
3,214
Location
bedlam
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.

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.
 
Back
Top Bottom