I bought two same kinds of fans, and have been happy with them for a few years. Not perfect, but they're on a HTPC that's a bit far, so it's OK.
However in the last few weeks I started to experiment with them to improve things - and noticed, that at BIOS's "AUTO" setting, my MB uses Voltage control instead of PWM (how odd, I'd presume PWM is preferred?). I know this, since in Linux, if I set to voltage controlled, pwm1 device read 2 (which means BIOS controlled), but at PWM control mode, pwm3 read 2. Both pwm1 and pwm3 devices control the same fan, with the exception that when controlling trough pwm1, the fan stops around ~60 (of maximum of 255, I need ~70 to restart), whereas when using pwm3, the range is from 1 to 255. So the pwm3 gives more precision in adjustement (oh, btw., pwm2 is my second fan, which, although is a 4-pin header in the MB; can only be voltage-controlled - according to BIOS options, and also in Linux; there's only 1 pwm file associated with it).
(Oh and sorry, the above may be gibberish to those who are not using Linux and / or are not familiar how the fan controlling works in linux
. In short, a pwmX is a file in sysfs, that represents the FAN controller, and is used by software to control the fan connected to it - or a priviledged user can fiddle with it manually. Every file has a pwmX_enable, that can be read to get the mode the fan is in, or written; 0=disabled (full speed), 1=manual (or software), 2=BIOS).
How can I deduce from the above that at AUTO setting, the BIOS uses voltage control instead of PWM? That brings me to the bottom line - and the reason I replied - is, that I noticed that when I use PWM with these fans (or the one that can be PWM-controlled) - they start to sing!
I mean, not in a nice way, but a very annoying way
. From Linuxes behaviour, readouts at pwmX_enable (0=disabled, 1=manual, 2=BIOS) and my ears I deduced the BIOS's behaviour (When I set BIOS to PWM, the singing starts, and goes away at "auto" or "voltage control" - or "disabled", for that matter; but also, if I set in Linux pwm3 to manual, the singing starts, but if pwm3 is disabled and pwm1 and manual, the singing stops).
The noise so annoying, that although PWM would be more accurate than voltage-controlled, it makes the whole purpose of controlling the fan speed moot since the "singing" - or whining, whirring, not sure which word I should use do describe it - is so annoying (even at 500RPM). Also, I have to note that the whining intensity is in no way connected to the RPM - it's only somewhat lower at a low RPM, as on a higher RPM - and non-existent (even at the same RPM, or actually any RPM) when voltage-controlled.
I've read in many places that some fans make a clicking sound when PWM-controlled, but this sounds anything but clicking to me. But it's probably related to those issues.
Also, I've had some stability issues on my MB (not too disturbing, they come and go away for a long time - and were GPU -related, I can compile away as much as I like without any issues). Also, I've noticed that the fans never really ramp up, even at high load, when BIOS-controlled. When I found this thread
, I started to wonder, that maybe the temperatures that I've seen (that I've thoguht were bogus, as Linux's lm_sensors doesn't actually tell from where a reading is made, and sometimes they are erroneus) actually are my NB temperatures (at idle, 85°C, at load, 98°C, or maybe have been even more since I haven't been watching - when fans are BIOS-controlled)!
So, after installing and enablign some SW fan controlling that really ramps up the fans when at full load, the stability issues seem to be gone. Either that or it was a loose cable I've havent found previously (I've been upgrading the hardware a bit, so something that was loose might have come properly inserted). Also, as a bonus, now my HTPC is more quiet at light load than it was before! (but, of course loud when doing something CPU/GPU/NB-intensive, like blasting demons heads off, but I wont hear the fans behind the shotgun noise anyways).
Doesn't help the OP, and the crappy BIOS control - but does re-instate that SW fan controlling is a solution in some cases - either for noise, but sometimes it's also inadequate for cooling. Just beware of the PWM, it can cause weird noises sometimes! Try voltage-control instead, it might not actually be the fan.
Just my 2¢, wanted to share my experiences.