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IDProjectCategoryView StatusLast Update
0001784SpeedFanFan controlpublic2018-12-25 10:17
Reporterbryanwieg Assigned Toalfredo  
Status acknowledgedResolutionopen 
PlatformBiostar a785g3OSWindows 7 
Product Version4.43 
Summary0001784: No case fan speed control
DescriptionSpeedfan Ver 4.44 Beta.

Sent Debug via Speedfan.

There is one 4 pin fan (for CPU) and one 3-pin sys fan. Speedfan controls the CPU fan fine. Speedfan is unable to control the sys fan.

I notice under the speed tab all speeds are listed as PWM, despite the fact that the Sys fan is a 3-pin fan which I understand to be voltage regulated.

For the IT8718F:
Fan 1 = CPU Fan
Fan 2 = Sys Fan
Fan 3-5 = Always 0, unknown.
Temp 1-3 = I believe are individual core temps.
Core = CPU temp (which is disabled when ACC is on)
Speed04 = CPU Fan

For the SB7xx/8xx PM2:
Fan 1: Avg 12 RPM, very wierd, I don't know what fan this is
Fan 2: Avg 2k rpm, I don't know what fan this is
Fan 3: always 0, unknown

TagsNo tags attached.
Motherboard ModelBiostar A785G3
Video Card Model



2011-04-11 09:24

reporter   ~0006102

Last edited: 2011-04-11 09:24

Changing the fan speed for the sys_fan is probably not possible on this motherboard. The motherboard's manual shows that the BIOS doesn't offer sys_fan control. The lack of BIOS control is a strong indicator that the necessary hardware parts for controlling the fan are missing on the motherboard.


2011-04-11 09:55

manager   ~0006104

I agree with norman02us.
Consider that a 3-pin fan can be controlled both using PWM and voltage. PWM is a way to simulate voltage changes.


2011-04-11 15:45

reporter   ~0006108

Last edited: 2011-04-11 16:29

Are you saying that a PWM 3-pin fan may be successfully controllable?

.. Or are you saying the by default 3-pin fans are controllable by PWM and voltage changes?


2012-01-18 09:04

reporter   ~0006799

Was this ever resolved? I have a TA770XE mobo and can see the system fans running, but do not get speed options for them.


2012-01-20 21:41

reporter   ~0006803

As stated above, there is nothing to solve here.

Take a look at the motherboards manual (or BIOS). If the BIOS doesn't show the speed or the control option for a fan, then the necessary hardware on the motherboard is probably missing.

If the hardware is not there, Speedfan can't do anything.

Issue History

Date Modified Username Field Change
2011-04-11 02:43 bryanwieg New Issue
2011-04-11 02:43 bryanwieg Status new => assigned
2011-04-11 02:43 bryanwieg Assigned To => alfredo
2011-04-11 09:24 norman02us Note Added: 0006102
2011-04-11 09:24 norman02us Note Edited: 0006102
2011-04-11 09:55 alfredo Note Added: 0006104
2011-04-11 09:55 alfredo Status assigned => acknowledged
2011-04-11 15:45 bryanwieg Note Added: 0006108
2011-04-11 16:29 bryanwieg Note Edited: 0006108
2012-01-18 09:04 dpallen77 Note Added: 0006799
2012-01-20 21:41 norman02us Note Added: 0006803