6 Fans via PWM?

[Atari]

Hi all,

I've bought a new case (In-Win 303) to replace my old one and I've got space for 6 fans. My mobo only has two fan 4 pin headers so I'm currently relying on a fan controller and a couple of 3 pin fans which I can't move to the new case due to it not having any 5.25" bays at the front.

Is there such a thing as a 1 to 6 way PWM fan splitter? I've tried a quick search but can't quite see what I'm looking at. Can anyone recommend a solution?

Thanks.

 

[doyll]

Swiftech and Phyobia make 8 way PWM hubs using PSU power.

But are you sure your 4-pin fan headers are actually PWM? It is very common to have 4-pin headers that aer not PWM, but only using 3 pins and are variable voltage, not PWM at all. PWM fans change speed on variable voltage and PWM, so simply plugging a PWM fan into a 4-pin fan header and have it change speed does not mean it is a PWM fan header.

 

[Atari]

Ah i see - being completely honest, I don't know much about the fans that I've got in the system. I had assumed all 4 pin ones were PWM, but if that's not the case, I may need to replace them all.

I'm gonna read up a little more into fans and see what's what - all of my fans currently are random ones I've bought over the years

 

[doyll]

It isn't so much the fans that are the potential problem, it's if your fan headers are PWM or not. That and the fact fan headers can only safely handle about 1 amp total load, and most fan ratings are running load, not startup. Startup load in amps is easily twice want the running load rating is. With PWM fans on a PWM hub with PSU power the fan header only supplies the PWM signal, not the fan power, and the PWM signal cannot be overloaded. It's kinda like a radio signal that gets weaker the farther away we get from it. The PWM fan signal can only supply signal to so many fans before the fans quit being controlled.

PWM fans receive constant 12v power and have a PWM control built into them that pulses that 12v power to their motor to control fan speed. The PWM signal from motherboard tells the fans when to pulse the 12v power to fan motor. That is over-simplified, but easiest way to explain it.

Fans with 3-pin plugs are variable voltage
Fans with 4-pin plugs are PWM.

What motherboard do you have?

 

[Atari]

It isn't so much the fans that are the potential problem, it's if your fan headers are PWM or not. That and the fact fan headers can only safely handle about 1 amp total load, and most fan ratings are running load, not startup. Startup load in amps is easily twice want the running load rating is. With PWM fans on a PWM hub with PSU power the fan header only supplies the PWM signal, not the fan power, and the PWM signal cannot be overloaded. It's kinda like a radio signal that gets weaker the farther away we get from it. The PWM fan signal can only supply signal to so many fans before the fans quit being controlled.

PWM fans receive constant 12v power and have a PWM control built into them that pulses that 12v power to their motor to control fan speed. The PWM signal from motherboard tells the fans when to pulse the 12v power to fan motor. That is over-simplified, but easiest way to explain it.

Fans with 3-pin plugs are variable voltage
Fans with 4-pin plugs are PWM.

What motherboard do you have?

That makes a hell of a lot of sense! What I wanted to do was to have a couple of fans in my case but to have them running at variable speeds depending on load, I had thought that they would all need to be PWM ones to do it!

I'm still running an old Gigabyte Z77MX-D3H which has 2x 4pin fan headers.

Thanks for the explanation - that's made a lot more sense!

 

[Tealc]

Gigabyte quite often have just the one PWM supporting fan header, usually the cpu_fan header.

Check you manual. If it says
1 Ground
2 12v/Control
3 Sense
4 Control or maybe PWM

Then it can be used for PWM or voltage.

1 Ground
2 Control
3 Sense
4 NC or VCC or 12v

Will mean no PWM control.

 

[doyll]

I looked at the manual and on page 24 it shows 3 fan headers; CPU_FAN, SYS_FAN1 and SYS_FAN2 (below PCIe sockets).
CPU_FAN and SYS-FAN2 appear to be PWM headers.

 

[Atari]

I looked at the manual and on page 24 it shows 3 fan headers; CPU_FAN, SYS_FAN1 and SYS_FAN2 (below PCIe sockets).
CPU_FAN and SYS-FAN2 appear to be PWM headers.

Must have missed that third one I built it into an old case I had knocking around a while back and it's been reasonably untouched since, it's only now that I've got a new case to build into that I'm looking into it

I'll rule out the PWM splitter then, is there anything in particular I should look out for in the powered hubs? Or any recommended ones?


Thanks.

 

[doyll]

Both the hubs and splitter I suggested are PWM controlled with PSU power and will do a good job for you. I think Silverstonetek have PWM hub with PSU power too.

 

[Atari]

Perfect - I'll grab one of those Thanks again for your help, its hugely appreciated.

Fingers crossed the system will be quiet with them installed. I've got some Fractal fans which were advertised as being quiet, but at anything below whatever the minimum is on my fan controller, they're deafening

 

[doyll]

Any questions or problem .. even if everything works as planned please let us know.

 

[Atari]

Any questions or problem .. even if everything works as planned please let us know.

Thanks again Doyll, I couldn't find the Swiftech one for sale but ordered the Phobya one - looks like it'll do the trick nicely.

Just before I start ordering some good fans, would I need SP variants for them, I understand they're for pushing through rads and restrictions, but I'm not sure if my case would count as it's got a dust filter at the bottom for intakes, and the top exhaust fans pass through a honeycomb type design in the metal



Would normal fans be required or SP variants?

Thanks.

 

[doyll]

I would use static pressure rated fans. The difference is static pressure fan make a little more noise at same rpm, but because they are able to overcome the resistance we measure as mm H2o and keep flowing a good volume of air at lower rpm than a similar fan with lower pressure rating, they end up flowing the needed air with same or less noise.

I hope that makes sense.

 

[Atari]

I would use static pressure rated fans. The difference is static pressure fan make a little more noise at same rpm, but because they are able to overcome the resistance we measure as mm H2o and keep flowing a good volume of air at lower rpm than a similar fan with lower pressure rating, they end up flowing the needed air with same or less noise.

I hope that makes sense.

Perfect sense - thanks again for your help!

I'll get some quiet SP fans on order, surprisingly temps aren't too bad in the case with only one bottom intake (which barely moves any air when I hover my hand over it) and no exhaust fans, but a few more should keep it much cooler I'd hope.

 

[doyll]

I was just looking at data for PH-F120MP fan on CoolingTechnique. You can see how much the pressure in mm H2o and CFM decreases as the rpm is lowered. At 600-800rpm it is only a fraction of what it is at full speed. Most of use don't what our case fans runnign above 950-1050rpm becuae we start to hear them.
http://www.coolingtechnique.com/rec...ne-phanteks-ph-tc12ls-e-ph-tc14s.html?start=5

 

[Atari]

I was just looking at data for PH-F120MP fan on CoolingTechnique. You can see how much the pressure in mm H2o and CFM decreases as the rpm is lowered. At 600-800rpm it is only a fraction of what it is at full speed. Most of use don't what our case fans runnign above 950-1050rpm becuae we start to hear them.
http://www.coolingtechnique.com/rec...ne-phanteks-ph-tc12ls-e-ph-tc14s.html?start=5

I was actually just reading at a review of those over on Thermal Bench I think it's either those Phanteks fans, or the EK Vardar 120ER, I like the reviews on the Noctua fans but the colours just aren't for me considering the side of the case is just one large piece of glass

I'd like some LED fans over the exhaust but I can't really find many that remain quiet (the Corsair ML 120 Pro's seem to have mixed reviews).