The problem with answering this question, is there is no way to
guarantee a motherboard supports such a function. Certain aspects
of the manual hint at a function, but that is not a guarantee it
actually works. For someone who really really wants this function,
it means having to buy more devices after the initial build, to
make up for the deficiencies. (I.e. If the motherboard doesn't have
it, you could easily spend as much as you spent on the motherboard,
to fix it.)
I looked in the manual, and the SYS_FAN2 header is a four pin type.
http://www.gigabyte.com.tw/Support/Motherboard/Manual_DownloadFile.aspx?FileType=Manual&FileID=18741
GND +12V RPM PWM
X X X X
But in the BIOS, the option to enable speed control, only exists
for the CPU fan. (The CPU fan that comes with the processor,
typically has a four pin connector, so if you buy a retail
processor, there are good odds you'll have control of the
CPU fan speed. Not all aftermarket CPU cooler fans use a four
pin connector.)
There are two speed control methods for fans. The older method,
is to adjust the +12V voltage to the fan. That takes a MOSFET
near the fan header on the motherboard (and that is how I'd detect
the feature on a motherboard). MOSFETs cost money, so you're
unlikely to find that control method present on a new board.
Prebuilt computers, like something from HP, are more likely
to have MOSFETs on all headers.
The four pin header, adds the PWM or Pulse Width Modulation method.
That is a logic signal, running at 25KHz (so it won't be audible),
where the pulse width of the square wave sent from the motherboard
to the fan, specifies the desired speed. A MOSFET on the fan, implements
the speed control. Thus the price of the fan should be higher, while
the motherboard maker doesn't have to provide the MOSFET on their end.
These are examples of a couple PWM fans. They aren't that common.
And in the case of your motherboard, it doesn't look like the BIOS
would control the speed in any case. (Speedfan from almico.com might
work, but we don't even know if PWM is wired up on the motherboard.)
*******
This Rexflo is a four pin PWM fan. The CFM rating isn't overwhelming.
Rexus also makes a 120mm but Newegg doesn't sell it.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835705027
This 120mm one is 96CFM at full throttle and 37CFM at low setting.
http://www.rexususa.com/fans/21225-4.html
They want $20 for that 120mm one, here.
http://www.frozencpu.com/products/5..._PWM_Fan_-_DF1212025BH-PWMG.html?tl=g36c15s69
*******
You can implement manual fan speed control, either with a rheobus
box that fits in a 5 1/4" slot in your computer. Or you can buy a
handful of Zalman Fanmate II fan speed adjusters (I think they
handle up to a 12V @ 0.5A fan). But then the cooling is not
automated, and the fans don't speed up when the computer is hot.
http://www.frozencpu.com/products/1002/bus-55/Sunbeam_4_Channel_Rheobus_-_Silver.html
There were some automated controllers in the past, but I don't even
remember the product names. (The nice ones may have come from
Germany.)
I see one here for example, but you don't want to buy stuff
like this, without some reviews to read. Some of these have
had just dreadful implementations. There are very few "winning"
designs. I remember one, which was covered with pin headers
(for stuff to plug in), and there was no positive alignment
of connectors. One user managed to plug the connector into
the wrong spot and poof! magic smoke. As a consequence, don't
buy crap like this, unless you've got way more info than the
seller or manufacturer is willing to provide.
http://www.frozencpu.com/products/7...ern-V_Fan_Controller_LCD_Display_-_Black.html
So nothing in the above post, really meets your expectations.
Paul
