Daisy chaining fans - Gigabyte EX-UD5

suitcase · 15 Oct 2010 at 22:16

If I were to use:

http://www.overclockers.co.uk/showproduct.php?prodid=CB-031-AK&groupid=701&catid=48&subcat=153

AND

http://cgi.ebay.co.uk/30cm-PWM-Y-Splitter-Cable---Black-Sleeved---BNIB-!!_W0QQitemZ190441777631QQcmdZViewItem?rvr_id=154076859041&rvr_id=154076859041&cguid=8e490a4012b0a0aa12007d30ffc9b602

with 4 Enermax cluster pwm (4 pin) fans.... connected to my motherboards CPU pwm fan header...

Would it work? i.e. all fans run at the same pwm controlled speed? Any issues with having 4 fans off one header?

Also, can someone confirm why the fans only seem to adjust between 1100rpm and 1300rpm when running off pwm? Is this purely because the cpu runs between 50 and 65c at any time and so the fans don't have a change to go slower?

Tealc · 15 Oct 2010 at 23:39

I was under the impression the Akasa splitter received power from a Molex rather than the motherboard, so it would be good for dozens of daisy changed fans as they would each get their PWM signal.

As for the speed thing I'd imagine that's down to the settings you have in place.

suitcase · 15 Oct 2010 at 23:46

Ah of course, so if the power is coming from the molex, the pwm signal is fine being passed to 4 and more fans presumably? It's not like the signal degrades or anything?

What settings do you refer to? The bios is set to pwm, auto. I've tried speedfan and gigabytes own software and they both do not seem to have any effect :-(

Greboth · 15 Oct 2010 at 23:56

Not to put you off that pwm splitter cable but I have yet to find out how to use that cable and get the fans to run on pwm. If I plug fans in using that cable they just run at 100%. I thought it would be as easy as plugging everything where it says to and it would work but apparently not.

GoogalyMoogaly · 16 Oct 2010 at 00:11

Greboth said:
Not to put you off that pwm splitter cable but I have yet to find out how to use that cable and get the fans to run on pwm. If I plug fans in using that cable they just run at 100%. I thought it would be as easy as plugging everything where it says to and it would work but apparently not.

I have the same issue with that splitter cable.

setter · 16 Oct 2010 at 00:49

Greboth said:
Not to put you off that pwm splitter cable but I have yet to find out how to use that cable and get the fans to run on pwm. If I plug fans in using that cable they just run at 100%. I thought it would be as easy as plugging everything where it says to and it would work but apparently not.

Must be a gigabyte board thing, ive uswed that cable on several asus boards, plug it in and off you go, ive used it with various pwm fans.

Essexraptor · 16 Oct 2010 at 03:54

suitcase said:
Ah of course, so if the power is coming from the molex, the pwm signal is fine being passed to 4 and more fans presumably? It's not like the signal degrades or anything?

What settings do you refer to? The bios is set to pwm, auto. I've tried speedfan and gigabytes own software and they both do not seem to have any effect

Bios

PC Health Status

CPU Smart Fan Control = Enabled

CPU Smart Fan Mode = PWM

Works for me!

The green wire on the akasa splitter carries the PWM control signal (which goes to the 2 4pin connectors only)

My guess is that you have 2 fans connected to the 2 to 1 4Pin PWM splitter to the 4 pin on the Akasa splitter and the other 2 fans connected to the 3 pin connectors on the Akasa splitter?

If so 2 fans would not get a control signal and run at full speed anyway the other 2 should have a variable speed if the above settings are applied in Bios

suitcase · 16 Oct 2010 at 11:42

I'm pretty sure the akasa lead makes them all work via pwm, so the only question is whether combining a splitter would cause and problems?

Also, any advance on why the fans currently only adjust between 1100rpm and 1300 rpm irrespective of temperature? I've run ITB and got the temp to early 90's and the fans still go no faster than 1300ish! And at idle they hover around 1100rpm. They're rated 500-1500rpm...

game4it · 16 Oct 2010 at 12:35

I run 5 pwm Akasa Apaches via 2 Akasa pwm splitters.
With fan control set to manual in the bios it works fine and enables me to use speedfan to adjust rpms from 500-1400ish.

I need each splitter powered by molex or all the fans wont run.I'd say its your "Y splitter" that your using with the powered pwm splitter thats causing the issues.

suitcase · 16 Oct 2010 at 16:52

How are your akasa pwm's connected? Each splitter to one 4 pin motherboard header? or one splitter daisychained off another from the cpu header?

game4it · 16 Oct 2010 at 21:21

suitcase said:
How are your akasa pwm's connected? Each splitter to one 4 pin motherboard header? or one splitter daisychained off another from the cpu header?

No,the first one is connected to mobo pwm header and the second is connected to one of the fan connections on the first splittler.
So you lose one possible fan connection.

2 splitter = upto 5 fans
3 splitter = 6 or 7 fans

Hope that makes sense as the only thing that i was thniking when typing that was "the knee bone is connected to the thigh bone........."

suitcase · 16 Oct 2010 at 21:40

Cheers for that. What motherboard is that on? I don't think my gigabyte will work with speedfan...

game4it · 16 Oct 2010 at 21:56

No worries,its an Evga sli le.

I havent used gigabyte in a long time so i cant comment on if it will let you use speedfan. It has to have some sort of software that will let you control the pwm manually i would imagine