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PWM hub, CPU cooler fan question.

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Hardware Man

Member
Joined
May 1, 2002
Location
The land of cheese.
Hard to believe but this is my first post since 2003, back when I built my first rig. Well, now I'm helping my son build his first rig and I have a question that I'm almost too embarrassed to ask because I know it has a simple answer. Anyway, he bought an Enthoo Pro ATX case. It comes with a PWM hub (something I'm not familiar with) and it has a cable that says to plug into the cpu fan header. So my stupid question is, if I plug the hub into the cpu fan header, where do I plug in the cpu fan? The cable on the fan is 4 pin and all of the connectors on the hub are 3 pin. Do I plug the cpu fan into the other 4-pin header on the motherboard, or can I plug the fan's 4-pin connector into one of the 3-pin connectors on the hub? I'm really not sure. Any help would be greatly appreciated. Thanks! :)

p.s. I hope this is the right thread to ask in.
 

marjamar

Member
Joined
Oct 29, 2010
Location
Loveland, CO, USA
PWM hubs basically provide multiple fan connections that look at the CPU fan connection on the motherboard for fan speed settings. All of the connected fans will run the same percentage of MAX RPM based on the CPU fan settings on the motherboard. Since all of the outputs on the hub are 3 pin, it will use lower voltage to the fans to control their RPM (less then MAX RPM) rather then PWM (pulse width modulation - On and Off pulse rate and duration). PWM controlled fans will work the same as non-PWM fans with 3 pin connectors, just not as good as it could work using 4 pins utilizing the PWM feature. Main advantage to PWM is more control and since the pulse is full voltage, they can run slower then non PWM fans can with more reliability.

Have fun on you son's new build!

-Rodger
 
OP
Hardware Man

Hardware Man

Member
Joined
May 1, 2002
Location
The land of cheese.
Thank you Rodger! I had read a few article's on PWM, but your explanation really helped me understand how it all works. So does that mean I can plug the 4-pin cpu fan into one of the connectors on the PWM hub? Thanks again!
 

Blaylock

"That Backfired" Senior Member
Joined
Jun 5, 2013
Location
Go Blue!
The main purpose for the hub is to allow all the case fans (or radiator fans if water cooling)to spin at the same rate. It also allows for a larger number of fans to be used than the board has headers. Personally I would plug the Hub into a different PWM header. You should still have full control through the motherboard settings. By keeping the CPU off the hub you will allow the CPU fan to ramp up when needed (CPU temp regulated curve) and the case fans to do the same (case temp regulated curve).

What's really surprising to me is you still remembered your password from 2003. That just baffles me.
 

marjamar

Member
Joined
Oct 29, 2010
Location
Loveland, CO, USA
Thank you Rodger! I had read a few article's on PWM, but your explanation really helped me understand how it all works. So does that mean I can plug the 4-pin cpu fan into one of the connectors on the PWM hub? Thanks again!
Yes. It will work fine that way, as long as the hub works as it should.

-Rodger
 

marjamar

Member
Joined
Oct 29, 2010
Location
Loveland, CO, USA
The main purpose for the hub is to allow all the case fans (or radiator fans if water cooling)to spin at the same rate. It also allows for a larger number of fans to be used than the board has headers. Personally I would plug the Hub into a different PWM header. You should still have full control through the motherboard settings. By keeping the CPU off the hub you will allow the CPU fan to ramp up when needed (CPU temp regulated curve) and the case fans to do the same (case temp regulated curve).

What's really surprising to me is you still remembered your password from 2003. That just baffles me.

This is the better way to use it. Also, I don't trust these cheap hubs too well as I have already burnt out some of the fan ports on a new Corsair Commander Pro trying to gang up two sets of 3 fans to 2 single fan ports (6 fans to 2 ports). This is how I did it for years using my Aquacomputer controller, but it is protected from over current and just does a reset if needed. Keeping the CPU fan plugged into the MB will allow you to control the CPU fan curves separate from the hub fan curves from a different header connection on the MB, so that will allow better flexibility.

-Rodger
 

Blaylock

"That Backfired" Senior Member
Joined
Jun 5, 2013
Location
Go Blue!
This is the better way to use it. Also, I don't trust these cheap hubs too well as I have already burnt out some of the fan ports on a new Corsair Commander Pro trying to gang up two sets of 3 fans to 2 single fan ports (6 fans to 2 ports). This is how I did it for years using my Aquacomputer controller, but it is protected from over current and just does a reset if needed. Keeping the CPU fan plugged into the MB will allow you to control the CPU fan curves separate from the hub fan curves from a different header connection on the MB, so that will allow better flexibility.

-Rodger

The hub that came with my Phanteks case is powered by a Sata connector so no worries there, as it doesn't draw the power from the header (TMK).
 
OP
Hardware Man

Hardware Man

Member
Joined
May 1, 2002
Location
The land of cheese.
The main purpose for the hub is to allow all the case fans (or radiator fans if water cooling)to spin at the same rate. It also allows for a larger number of fans to be used than the board has headers. Personally I would plug the Hub into a different PWM header. You should still have full control through the motherboard settings. By keeping the CPU off the hub you will allow the CPU fan to ramp up when needed (CPU temp regulated curve) and the case fans to do the same (case temp regulated curve).

What's really surprising to me is you still remembered your password from 2003. That just baffles me.

I hadn't tried that, but I saw the other 4-pin header on the motherboard and wondered if that would work. I'm going to try that when I get home tonight. Now that I understand how the hub works I think I'm going to like it. My son wants to add water cooling at some point (when his budget allows it) and I think the hub will come in handy then. Speaking of water cooling, I can't believe far it has come since I built my first rig. Supplies were pretty rudimentary back then. I even had a friend with access to a CNC machine make me a cpu water block from a solid piece of copper. Those were the days...

By the way, I had to use the "forgot my password" routine before I could logon. :D

- - - Updated - - -

The hub that came with my Phanteks case is powered by a Sata connector so no worries there, as it doesn't draw the power from the header (TMK).

Same with the case my son bought. Funny though, the case fans are hooked up to the hub but didn't turn on when we turned the computer on. I assume in addition to the Sata power that I need to hook the hub to the fan header on the motherboard before they will work?
 

ATMINSIDE

Sim Racing Aficionado Co-Owner
Joined
Jun 28, 2012
If the SATA connector is getting 12V, the fans should too. Is the motherboard in the PC? If not, how are you jumping the PSU?
 
OP
Hardware Man

Hardware Man

Member
Joined
May 1, 2002
Location
The land of cheese.
If the SATA connector is getting 12V, the fans should too. Is the motherboard in the PC? If not, how are you jumping the PSU?

The motherboard is installed in the case. The Sata power is plugged into the same cable as the DVD player, which has power. Is there a way to check the hub for power?
 

ATMINSIDE

Sim Racing Aficionado Co-Owner
Joined
Jun 28, 2012
Yes, you can use a digital multimeter. Pins 1 and 2 for a fan should be giving 12V.
If that is not working, check that the SATA connector is getting 12V to it.
 

Blaylock

"That Backfired" Senior Member
Joined
Jun 5, 2013
Location
Go Blue!
I'm just theorizing here but if the PWM hub doesn't receive a PWM signal from the Mobo it wont turn the fans on. Yes, You may need to plug in the Hub to the MoBo.
 
OP
Hardware Man

Hardware Man

Member
Joined
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Location
The land of cheese.
Thanks ATMINSIDE and Blaylock for the tips. The first thing I'll try when I get home is plugging the hub into the other 4-pin header on the motherboard. If that doesn't work, I'll find myself a multimeter and check the voltages. Thanks again.