Scythe fans and the CPU fan connector? Confused...

bhuether · Post by **bhuether** » Thu Sep 27, 2007 11:05 pm

The CPU fan connector on the ASUS P5K is a 4 pin connector. The Scythe fans have 3 pin connectors. What am I supposed to do?

thanks,

brian

eztiger2 · Post by **eztiger2** » Fri Sep 28, 2007 12:23 am

Plug it in?

The 4 pin connector on my p5k makes it quite clear which pins to use when plugging in a 3 pin fan connector (it has the little 'ridge' to ensure it goes in correctly).

I have a nexus real silent plugged into it via a 3 pin connector. I can't get speedfan (or the Asus q-fan stuff) to control its speed though so be aware if thats a concern.

Kev

bhuether · Post by **bhuether** » Fri Sep 28, 2007 3:34 am

Damn... so none of the Scythe fans will work with SpeedFan? How do you apply any control to those fans? Through a fan controller?

thanks,

brian

Alex · Post by **Alex** » Fri Sep 28, 2007 4:04 am

Plug it in to another fan header that Speedfan can control.
I happen to have 5 of those on my Asus Commando Mobo.

It can be helpful to choose "Ignore" on CPU FAN RPM reporting in the BIOS (Hardware Monitor tab in my BIOS) otherwise you will get a warning about that (CPU FAN 0 RPM) at bootup.

You can use a "Y" cable splitter so you can share one fan connector for 2 fans if that helps (only one of them will be RPM monitored).

Otherwise I guess you must get a noisy 4-pin PWM fan.

eztiger2 · Post by **eztiger2** » Fri Sep 28, 2007 4:05 am

I can control my other nexus fans on the motherboard system fan headers with no problems - I think its just that single 4 pin CPU fan header can't be controlled. It shows up and speedfan can get the current rpm's, but chaging the speed doesn't do much.

But I could have been doing something wrong or perhaps the Nexus can't be controlled through it for whatever reason. I didn't mange to get *any* of the asus q-fan stuff working either which might lend some weight to the first option!

If you do want to use speedfan I found I had to disable the Q-fan stuff in the BIOS before it would be controllable.

So yes, through a Fan controller - or connect your scythe to a system / chassis fan header on the motherboard and control it from speedfan that way.

You'll get a post warning that no CPU fan was detected but you can (presumably) disable that warning.

I need to look into that myself, but only built the box this week so havn't got round to it

I'd be interested to hear how you get on if you try any of the above.

Kev

Alex · Post by **Alex** » Fri Sep 28, 2007 5:41 am

To eztiger2
3-pin CPU fan can not be controlled (at least not on my superb Asus mobo), this applies to Asus Q-Fan also (=do not use with 3-pin fan).

I've heard Abit has good BIOS solution for fan control.

Solution:
- use another connector
or
- get a "noisy" 4-pin fan
or
- maybe (don't know if it works) get an Abit mobo

eztiger2 · Post by **eztiger2** » Fri Sep 28, 2007 6:53 am

I've had a bad run with abit boards recently, I'm sticking to ASUS for now!

Thanks for the info though, good to know I'm not doing anything too stupid.

I take it from your comments there are no good quiet 4 pin fans available?

Kev

Alex · Post by **Alex** » Fri Sep 28, 2007 7:54 am

eztiger2 wrote:I've had a bad run with abit boards recently, I'm sticking to ASUS for now!

Thanks for the info though, good to know I'm not doing anything too stupid.

I take it from your comments there are no good quiet 4 pin fans available?

Kev

Yes, there are in fact almost no other 4-pin fans except the CPU bundled ones.

bhuether · Post by **bhuether** » Fri Sep 28, 2007 11:04 am

I noticed the chassis fans are 12V but I always see people around here talking about running fans at 5V... Yet something else to add to my confusion...

thanks,

brian

crabnebula · Post by **crabnebula** » Tue Oct 02, 2007 9:18 pm

People undervolt them so they run slower and quieter. This is how SpeedFan controls chassis fans as well.

merlin · Post by **merlin** » Tue Oct 02, 2007 10:16 pm

You might want to just consider a hardware solution, the easiest being some sort of fan voltage control such as a zalman fanmate 2 or any of the fan controller bays.

cmthomson · Post by **cmthomson** » Thu Oct 11, 2007 1:47 pm

The P5K, unlike many of its higher-priced companions such as the P5B or P5W, lacks the ability to control a 3-pin fan connected to the 4-pin CPU header. On other boards, there is an option in the BIOS to run this header in "PWM" or "DC" mode (ie, in 4-pin or 3-pin mode), but the P5K does not have this option.

It is able to control the speed of a 3-pin fan connected to the CHA1 or CHA2 header, but there is only one controller for both these headers. So if you want to have only one variable-speed fan in your system (or two that run in lock-step), use these headers.

crabnebula · Post by **crabnebula** » Thu Oct 11, 2007 8:48 pm

cmthomson wrote:The P5K, unlike many of its higher-priced companions such as the P5B or P5W, lacks the ability to control a 3-pin fan connected to the 4-pin CPU header. On other boards, there is an option in the BIOS to run this header in "PWM" or "DC" mode (ie, in 4-pin or 3-pin mode), but the P5K does not have this option.

I actually sent a request to Asus to add that feature to the BIOS. It should be a simple matter of using different settings on the Winbond IO chip. The latest SpeedFan v. 4.33 allows you to do this, but selecting DC ouptut for the CPU fan controller doesn't seem to have any effect. Not sure why, I assume it is somehow overridden by the BIOS.

orihara · Post by **orihara** » Fri Oct 12, 2007 7:51 am

The P5B can't control a 3pin fan on the CPU header either. I think it may be that they didn't include the circuitry to do so.

Scythe fans and the CPU fan connector? Confused...

Scythe fans and the CPU fan connector? Confused...

Re: Scythe fans and the CPU fan connector? Confused...