I'm looking to replace my CPU/motherboard (Abit IP35 Pro) with a low-powered and budget combination. Back in the day, the Abit IP35 Pro was seen as one of the leaders in the department of fan speed management. From what I've been reading it seems almost all manufacturers allow you to exert some sort of control over voltages to the fan headers and/or the 5V+ leads to the PWM-based fan headers. Is there some truth to this, or is there generally one or two manufacturers that just "gets it" in terms of control over fan speeds. The choice of micro ATX boards in the low to mid range is simply staggering. Thanks for any advice.

imo it comes down to the type of fans you want to control and how, and what fans also matter as some will undervolt fine others wont.

For windows based pc, if you don't mind running software, and yor fans are 3pin except the cpu fan, i would chose asus with fan expert.

For a windows o none windows based pc, with bios fan control in mind, and using pwm fans and fan splitters, then i would go with msi (asrock seems a good choice as well but i dont own onw to know for sure).

all manufacturer have h97 motherboard around $100 to 120, so that would be what i would suggest.

Thanks for the reply. Do all the Asus boards pretty much have only one PWM header? I really would like to avoid anything in software and read often that Asus boards are the best. This will be for an HTPC with two 120mm case fans side by side very close to the CPU. So, I will need no CPU fan. I suppose I would only need one PWM header with a Y adapter for both fans? How would the BIOS read the fan speed if 2 fans are connected?

Some such as the Z97 Deluxe have several PWM headers but it seems that most of the recent Asus H97/Z97 boards feature BIOS fan tuning which may enable 3 pin fan speeds to be optimized without the use of supplementary (Windows) software.The PWM Y adapters have one socket with 4 pins connected and one socket with 3 pins connected. The 4 pin socket includes the fan speed reading so that the BIOS only receives one fan speed signal.

OK thanks. I'm looking at the H87 (microATX)boards at the moment, and they too, seem to be updated with respect to the Z87 boards. The H87 features three true PWM 4-pin fan headers (2 CHA + 1 CPU), in contrast to the Z87 "fake" 4-pin headers. The two CHA headers can be adjusted with a duty cycle between 60-100% and the CPU header from 20-100%.

It specifically states in the manual that ONLY 4-pin fans can be supported by the fan software. So, with this board, it seems that 3-pin fans would only run at full speed (+12V). To me, this doesn't seem to be a satisfactory answer to keeping your system quiet if you have 3-pin fans. From the manual:

It would appear then that there's no fancy switch in the header to detect whether to run in voltage- or PWM-mode.

As for your comment regarding the y-adapters, my question was geared to running 2 of the same sort of fan to one header, in which case you would need a y-adapter. How would the sensor get its info?

The CHA headers fall into the 'fake' category because they ought to provide the same duty cycle range as the CPU PWM header. 60-100% duty cycle is approximately equivalent to 7 to 12V control for a three pin fan, this to me seems OK as a reasonable range of thermal control that should work with just about any 3 pin fan. However 60% may be too high a setting for the PWM fans that can drop down to the 20% or 30% level. This of course only applies to BIOS settings. Running the Asus Fan Xpert software will enable fan speeds to be reduced, but how much depends on the fan concerned. Plus of course you need to be running Windows, and don't mind using fan control software.Not with the H87/Z87 boards but see below.The CPU PWM header outputs 12v negative and positive and a duty cycle setting signal. The Y adapter simply splits these three outputs between two fans. The duty cycle setting is based on motherboard chipset temperature readings, so can take account of both system stress and ambient temperature conditions. Motherboard PWM fan control is 'closed-loop' so it also needs to be able to read the fan speed. So if for example the fan speed is 0 rpm the chipset will continue raising the PWM duty cycle setting until the fan starts and a rpm reading is detected. With a PWM Y adapter it needs to only read this from one of the two fans, it is your choice as to which one it is. As the two fans share a duty cycle setting they can be of different specifications but may run at different speeds with the same duty cycle setting.

In summary, if your budget will stand it it might be worth considering a Z97 board such as the Asus Z97M-PLUS. According to Asus the BIOS tuning of the motherboard will work with both 3 pin and PWM fans, and it would avoid the need to use both PWM splitters and supplementary fan control software like Fan Xpert. There would also be an individual speed reading available for every fan in the system.

Well i would put that Asus is a pretty good motherboard manufacturer, but the best idk, there are different boards from all manufacturers and most are good, it really depends on what you are looking. For my intended purposes Asus for me its the worst, as it has high restrictions on pure bios fan control, i dont like to run extra software to control fans, and in the case for asus to have good control you do need it, at least thats my opinion. There are better option that fit more what im looking, like MSI (and i think AsRock) that have better bios fan control. But i still continue to recommend asus, because even though its not the right fit for me, they do produce good motherboards and for someone looking for an easy quiet setup, Asus + FanXpert works pretty good.

Look into MSI and AsRock, in certain motherboards they offer 2 PWM fan headers, in MSI is CPU_FAN1 and CPU_FAN2, in AsRock i believe is CPU_FAN and SYS_FAN1 (you have to crosscheck this), but its not on all motherboards you do have to check it for each.

Asus H87 motherboards will only have 1 true pwm fan header, H97 might have more according to what loadstar have posted, i cant confirm it as i dont own one to say for sure.

Be careful as Asus tends to lies in some aspects, like whats PWM or voltage controlled, thats up to Z87/H87/H81, suppose to change on H97/Z97, but i dont expect it to change, again i dont own recent motherboards to say.

On fanXpert2, on an H87 motherboard, you will be able to control both CPU_FAN (real 4pin PWM) and CHA_FAN (fake 4pin, voltage controlled), its just a matter of loading AI Suite III and run the tunning, then you can adjust the graphs to what you like. But the important thing is to understand how Asus motherboards are design, specially the fan headers, and chose the correct fans for each. CPU_FAN you can go with 4pin PWM (or 3pin fans changing in the bios from AUTO to ADVANCED), on CHA_FAN headers use 3pin fans only.

On Asus motherboards, at least that ones that i have owned, there is an option inside the bios called Q-FAN, if its seleceted AUTO = 4pin PWM, if ADVANCE is selected = 3pin voltage control, this was only available on CPU_FAN header on my motherboards, on the new Asus H97/Z97 it seems that this has been implemented to the chassis headers, but i cant confirm this as i dont own one.



When you use a 4pin PWM fan splitter, one of the ends remain 4pin (current, ground, rpms and PWM), while the other is 3pin (current, ground, and PWM), this means only 1 fan will report the rpms for both, usually works fine as long as you use the same fan on both ends. There are more fancy PWM splitters that draw power from 4pin molex or Sata power, but the principal is the same, only 1 fan reports the rpms, but all get current, ground and pwm singal.

If you are only going to run 2x 120mm PWM fans, and both are the same brand or model, and you want pure bios fan control, no software. Then go with MSI and get PWM fan splitter and run both fans from the CPU_FAN header, enter the bios and set the fan curve. If you want to control each fan individually, search for MSI motherboard with CPU_FAN1 and CPU_FAN2, here a pictures of my setup controlling CPU_FAN1 and CPU_FAN2 headers on pure bios.

OK thanks for the replies. It looks like this H87M-plus board is a complete other animal. No where does it mention anything about voltage or DC control of the CPU fan in the manual. And, no auto or advanced in the q-fan section either to force a PWM or 3-pin fan control. It looks like only a PWM control at the CPU header. MSI is the same in this segment (mid range). From what it appears and from what others have reported MSI works the similarly, in that only PWM fans are controllable in the BIOS at the CPU. It looks like only ASRock has BOTH a 3 pin and a 4-pin header for the CPU and CHA, giving you the choice at both locations (CPU and CHA).

To what i have tested, the only board that has the switching between PWM and 3pin is Asus, MSI doesnt have anything like that, i believe asrock doesnt either. But you can undervolt PWM fans, some say its not design to work like that, and you can ruin them, but what i have found out in my testing is that some brands of pwm fans are not stable, for example some noctua pwm fans stopped ran on fanXpert2, but a small bump on the graph would fix it. Either way, my suggestion is go by what others have experieenced and not by manuals or manufacturers marketing, else you will risk experiencing issues like the Fake 4pin etc.

No, I meant that ASRock in this segment has 2 physical headers for CPU. So, there's 3-pin CPU, 4-pin CPU, 3-pin CHA, and 4-pin CHA. No fuss and clear as day, each with their own controls, and in the BIOS to boot. And yeah, I agree it's best to get experience here from others and not rely too heavily on the bad info in some of the manuals.

Here is where i cant help you much, to what i have read, some AsRock motherboards have 2 true PWM fan headers CPU_FAN and SYS_FAN1 (but not all). AsRock bios fan control seems pretty good though for pwm fan headers, it has increments of 1%, while MSI has 12.5%, but this only applies to the PWM headers, for the standard 3pin (aka meaning other SYS_FAN headers) their bios fan control is meh, like only preset profiles (silent, normal, etc). MSI is similar good control on bios PWM headers, but meh on others, it has 50% restriction on CHA_FAN headers, not a big deal if you plan accordingly on the fans you chose, but this i say to warn you that not all headers are good on bios fan control, some will have higher restrictions than others, but i would go with MSI or Asrock if you want pure bios fan control, specially if you are going with PWM fan headers.