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Fan RPM different each time I boot up


soopytwist

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As mentioned in other posts I now have two SP120 Performance fans on my H100i using the volt reducer wires to quieten them down. I ditched Corsair Link because it won't control the SP120's, this means I have no control over speeds - they are what they are. Not even Asus Fan Xpert+ can control them because they're not 4-pin fans.

 

Every time I boot my PC I get different RPM readings from the fans.

Just now after booting up for the first time today the RPM for both was barely over 1000, which may explain why the CPU temp shot up to 40C on idle and the motherboard about the same. Again, can't change speeds myself.

 

Rebooted and now they're both 1200 RPM and CPU temp is now 28C and motherboard 37C.

 

So why the change in speeds? Presumably the change is in the voltages, why change at all?

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True, the CPU fan header will only control PWM fans but on the P9X79 any of the other fan headers will control 3-pin fans. Why ASUS designed it this way? who knows....

 

Not true, at least not for the P9X79. I have the SP120's connected to CHA_FAN3 and CHA_FAN4 (both chassis headers) and Asus Fan Xpert+ won't control the speeds.

 

Don't you mean it's the other way around, CPU headers control 3-pin and the other headers control 4-pin only?

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You had it right the first time cpu header will only control 4-pin PWM fans. The other fan headers CHA_FAN3 and CHA_FAN4 can be controlled with AI Suite. In the bios under advanced, monitor, Q-fan should be enabled for all fan headers.
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You had it right the first time cpu header will only control 4-pin PWM fans. The other fan headers CHA_FAN3 and CHA_FAN4 can be controlled with AI Suite. In the bios under advanced, monitor, Q-fan should be enabled for all fan headers.

 

Q-Fan is enabled for all, and my 3-pin SP120's on the H100i are connected to CHA-FAN3 and 4 so why can't I change their speeds?

 

http://i33.photobucket.com/albums/d94/soopytwist/New%20PC/Untitled2_zps073018b8.jpg

 

Chassis fan 4 is set to max RPM, yet hovers around 1300 rpm. Also CPU fan OPT to Chassis fan 4 are all greyed out.

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In Fan Xpert setting should be user, using your mouse click and drag the left blue dot down to the temp and % you want to set your fan at then click apply. The other two you can adjust for whatever parameters you like. Or in settings use one of the predefined fan curves.
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I've just ticked all fans in Probe II and I'd already dragged those blue dots to 100% but the fans stay put at one speed.

 

The only fans I CAN change the speed of are:

Chassis fan 1 (CHA_FAN1 - rear exhaust) 3-pin 120mm Corsair SP120 Performance

Chassis fan 2 (CHA_FAN2 - front intake) 3-pin 200mm Coolermaster Megaflow

 

The fans I CANNOT change the speed of are:

Chassis fan 3 (CHA-FAN3 - H100i) 3-pin 120mm Corsair SP120 Performance with volt reducer

Chassis fan 4 (CHA_FAN4 - H100i) 3-pin 120mm Corsair SP120 Performance with volt reducer

 

The fans I don't touch are:

CPU fan (CPU_FAN - H100i pump) 3-pin and PSU molex

 

CPU_OPT - front 120mm original 600T rear exhaust fan (because it's quiet)

This fan does not show in Fan Xpert+ at all so I wouldn't be able to change the speed of it even if I could.

 

Today first turning on, fans 3 and 4 were at 800 rpm and my CPU quickly began to sweat. Reboot and they're 1024 rpm approx. Reboot again and they're now 1159 and 1170, CPU at 28C idle. If I reboot again I betcha' they're go up to 1200 rpm where they stay and won't get any faster than that despite being Performance fans but that could be volt reducer. 1200 rpm is fine I just wish they'd be that speed from the get go.

 

http://i33.photobucket.com/albums/d94/soopytwist/New%20PC/Untitled3_zps4037c8a7.jpg

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Another reboot and now fan 3 is 1160 rpm and fan 4 is 1020

 

EDIT

 

I found this on tom's hardware forum:

 

Had a response from Asus to say that the P9X79 Pro chassis fan headers are not PWM (?!) only the CPU headers are.

 

I've asked for clarification as these are 4 pin headers, and are advertised as PWM.

 

Like everything else on forums across the internet - there's no update.

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I now have 4-pin PWM fans from Corsair but I still don't want to use Corsair Link. Even with these fans in CHA_FAN3 and CHA_FAN4 I can't change their speeds in Fan Xpert+, and they're locked at 1645 and 1630 and vary around those numbers.

 

Is my motherboard faulty or what?

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I found version 1.01.15 of Fan Xpert+ on the Asus download page. With this I can now control the fan speeds of all my fans! I still have the Corsair 4-pin PWM fans on at the moment so I'm going to try the SP120's again and if I can control those as well.

 

So the solution seems to be installinf version 1.01.15 of Fan Xpert+ to control all the fan headers on the P9X79 Deluxe motherboard.

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