Intel Motherboards : Asrock Bios fan control is it equal on all models

Author: 11mail22
Subject: Asrock Bios fan control is it equal on all models
Posted: 26 Nov 2016 at 6:51pm

Here my story about FAN control on the ASRock Z170 Gaming K4 board.

First of all I want to mention in this thermal thread, that I am glad to decide for Gaming K4 instead of MSI Tomahawk, as the 45% larger Z170 heat sink is valuable. This device are really a heater. But back to FAN control.

My Miditower has 5 DC controlled Fans, but the board just have two ports to control that (CPU_FAN1 and CHA_FAN1) as ASRock decided to save some cents (which MSI does not). The layout is prepared for each port, but the FAN vontage regulator device for this 3pin mode is just mounted at two of them. My thought was to connect two FANs in parallel to one FAN port of the mobo.

So I meassured the power consumtion of a single 12cm fan:

0.13mA@12V, 0.11A@10V, 0,09A@8V, 0,07A@6V Startup: 5V

The FAN voltage regulator device is a Nuvoto 3943S which is similar to http://www.nuvoton.com/hq/products/power-management/voltage-regulators/fan-driver-ic-series/%3F__locale=en confirmed by customer support of Nuvoto (Thank you for that).

This is the important information in this datasheet (beside the 500mA drive capability)

PD(MAX) = (TJ(MAX) - TA) / θJAWhere TJ(MAX) is the maximum operation junction temperature 125?? TA is the ambient temperatureand the θJA is the junction to ambient thermal resistance. θJA for ESOP-8 package is 75??W onJEDEC51-7 (4 layers, 2S2P) thermal test board with minimum copper area. The maximum powerdissipation at TA = 25??can be calculated as:PD(MAX) = (125??- 25?? / 75??W = 1.33W

As lower the fan should run, as more power will be converted to heat in this device (MOSFET). dP = dV*I.

For my parallel FANs this result in (12V-6V)*2*0,07A = 0.84W so it will work. In practice this small device which is well thermal connected to the board (look at the spare foot prints), get really warm. You cant put your small finger longer time on that. So ~60°C.

If you have similar thoughts please check your fans carefully. My lighted top FANs does have 0.08A@5V (startup 3V), which already lead to the maximum of 1.33W of the device.

Finally I put the back fan to CPU1_FAN and both front fans in parallel to CHA1_FAN. The two lighted top fans are in serial (2x6V) direct to 12V.

My only PWM fan (4 pole) is the Arctic Freezer 13. Connected to CPU2_FAN, but at lower speed I got strange buzzing noises, coming for the power supply (guess a bad coil). I tried CHA4_FAN and this works absolutely silent. So keep in mind, lower speed is more critcal for you board.

The controlling in the BIOS or App is customized, as only there I know what happen and can perfectly adapted to my FANs noise profile. It can be done very accurate by single % steps, which already changes the noise behavior of the fan.

ASRock should really spent at each port that 3pin option, as MSI do.

Edited by 11mail22 - 21 hours 54 minutes ago at 6:54pm