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IDProjectCategoryView StatusLast Update
0002168SpeedFanOtherpublic2019-04-02 06:33
ReporterMrPeteH Assigned Toalfredo  
Status assignedResolutionopen 
PlatformASrock z77 Extreme6OSWindows 7OS Versionx64
Product Version4.49 
Summary0002168: Documentation of hard-to-find data on NCT6776F controller (ASrock z77 Extreme6 etc)
DescriptionThis info is not available from the motherboard manufacturer nor easily found online. I downloaded the data sheet from Nuvoton and deciphered the data below.

This chipset supports five fan inputs and three outputs:

CPU in/out - PWM
Sys in/out - PWM or Analog voltage control
Aux0 in/out - PWM
Aux1 in
Aux2 in

On the z77 extreme6 mobo, these are mapped as follows:
   CPU fan => Four pin CPU1 mux'd with CPU2
   Sys fan => Four pin Chassis Fan 1
   Aux0 => Three pin Power Fan (!!! Can't do PWM because no fourth pin)
   Aux1 => Three pin Chassis Fan 2
   Aux2 => Three pin Chassis Fan 3

Four fan control modes are supported. The numbers are bit values to set each mode:

0) Manual - direct setting of percent/pulse rate
1) Thermal Cruise - auto seek specified temperature
2) Fan Speed Cruise - auto seek specified fan speed
4) Smart Fan IV - fan speed curve with four set points and hysteresis

Note: all auto-control modes (Thermal, Speed, Smart) have user-settable temperature source, which can be any sensor known to the chip. By default, CPU speed source is CPU temp, Sys speed is Sys temp, Aux speed is Aux temp.

Manual - direct setting. This is the only mode controlled by SpeedFan

Thermal Cruise
* Setting: target temp, minimum fan speed, temp tolerance (ie +/- degrees).
* Fan runs at minimum set speed if very cool, 100% if very high, fan stable once target temp is hit.
* Note: BIOS typically does not allow setting the tolerance. Suggested tolerance is 3 (degrees C).
* Note: there are many other settings, eg minimum start speed, change rate (default 1 sec PWM, 4 sec DC)

Fan Speed Cruise
* Setting: target speed
* Fan PWM pulse rate (or DC voltage) is modified until the desired RPM is achieved
* Note: I've not yet seen a BIOS that supports this

Smart Fan IV
* Settings: four sets of target temp and fan speed, plus hysteresis values and other parameters
* Appears similar to a simplified version of SpeedFan, but have not found BIOS or software able to properly set this up.
Steps To Reproducen/a
Additional InformationI just found an online copy here:
TagsNo tags attached.
Motherboard ModelASrock x77 Extreme6
Video Card Modeln/a


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Issue History

Date Modified Username Field Change
2013-08-31 23:23 MrPeteH New Issue
2013-08-31 23:23 MrPeteH Status new => assigned
2013-08-31 23:23 MrPeteH Assigned To => alfredo