Originally Posted by PinkoTheCommi
I am experiencing something strange with my PWM fan hub, or is this normal?
Anyways, here is my setup in regards to the PWM fan hub:
I have an Asus Z87-A, the fan hub PWM connector is plugged into my CPU_FAN header
, the only true PWM header on this motherboard, just as the manual instructs us to do. I do not have the SATA power plugged in
I get a controllable range of 30-100%, w
hich is weird because for a true PWM, I was expecting full 0-100%, at least when I had my CPU/Radiator fans plugged into CPU_FAN I had full 0-100% control. In my Chassis Fan headers, which are "fake" PWM headers I get 30/40-100% control depending on the fan being used. I have yet to try the Fan Hub's 4-pin into a Chassis Fan header, I will try that when I am done typing this.
That is not my complaint though. My complaint is that all of my fans that are connected to the Fan Hub are not staying at the constant speed that I set. They seem to be fluttering at +- 200rpm
. I will set the RPM to 1,000 but the fans that are connected to the fan hub seem to be bouncing up and down. It will go up to 1,200 for a second and then back down to 1,000. I can tell this because Fan Xpert II and HWiNFO gives me real time info on the fan speed, and because I can hear the noise when the fan is constantly going up and down in speed. At least they don't go below what I have set, but I really don't like the constant noise of the fans ramping up and down. I run all of my fans through Asus Fan Xpert II, and I prefer RPM mode. I tried Smart Mode,
but the problem persists.
The instructions were not crystal clear, so I tried plugging in the SATA Power connector in addition to it already being plugged into the CPU_FAN header, they were both plugged in. When I did that, the controllable range was like 90-100% RPM.
So that is a no go, and the same problem continues of the fans going up and down in speed.Any idea what I can do about this constant up and down in fan speed?
I want to attach my AIO's Pump header onto the fan hub, so that I can free up a chassis fan header, but I don't think the constant up-down is good for a pump.
Another question I have is regarding the 140mm included Phanteks Fan. My fan blade piece seems to be jockeying back and forth within its frame,
it looks like it is about to fall out and doesn't appear to have the most "even" of spins. I have never used a Phanteks Fan before, is this how they are designed to run? I have a lot of different fans, from different companies and with different prices, I have never seen a fan do this. Could someone please confirm that this is how they are supposed to run? Or do I have a damaged fan from the toolbox coming loose?
Without the power Molex and IF true PWM header you are running all fans from the MB header... not the best of ideas.
Control 30% -100 %
Yes, that is normal, INTEL says so, Minimum PWM is 30% , otherwise it is considered an error condition (eg stall or no fan present)
Some fluctuation is normal..
Either the system is reacting to changing conditions in the case (eg PSU/GPU fan ramps up)
or by some "rounding errors" in the RPM interpretation
or by insufficient signal/power on the MB header... eg too many fans and/or load exceeds 1/2Amp - this will kill the MB in the long run
or... Fan control applications (eg speed fan FAnXpert) are fighting to wrestle fan control away from ASUS "Smart Fan"
In this case, I blame SmartFan being too smart for its own good and trying to work out min-max/ramp on its own.. tell it to comply with your commands. You dont need any extra fan control software.. either the BIOS handles it or not.
If fans go to 100% when pluggin in the power molex, you are not using PWM mode on the MB header
I you dont use smart mode, but RPM you are Voltage controllingAny idea what I can do about this constant up and down in fan speed?
A capacitor inline to "buffer" to voltage change maybe?
OR you can set the curve point differently iso of <45°C run at 30% , set to <45°C run at 35% or 40%
The fan "wobble" is caused by the "Floating" bearing design. Its "very loose" on the axle. Its a sleeve bearing variant. Which means they should be operated vertically.. or.. as INTAKES when mounted to the roof of the case (and EXHAUST when mounted on the floor).
It "lifts" itself up a bit from the bearing when running. Which means there is an optimal "lift height"... factors like mounting upside down can affect this operation. ... Dont know how much impact on MTBF that has though.
Anyways, since these are Sleeve Bearing variants, the same rules as with other sleeve bearing variant apply... only mount them vertical if you want longlivity.
Fan HUB explained: