No automatic fan speed control for system fans on Z170XP-SLI

[GurtTractor]

Hello. After considerable testing to try and get my system fans to change their speed based on CPU temperature I've come to the conclusion that there may be something wrong with my Z170XP-SLI motherboard. I am using an i5 6600k and Windows 10. I have yet to recieve a reply from Gigabyte about this.

I have tried all possible configurations with my fans, which are a mix of 3-pin and 4-pin PWM and different sizes and brands. I've tried today with a new Noctua PWM fan in the various SYS_FAN headers and it would not speed up under a stress test. I monitor the speeds with HWMonitor and by checking them physically and listening to them to see if they are speeding up.

The CPU and CPU_OPT fans headers will automatically variate and as a temporary measure to have some case fans speed up under load I've connected a 120mm and 140mm to the CPU_OPT with a Y splitter, which does allow them to ramp up.

I can set the system fans to full speed from the BIOS, but any of the automatic settings do not work. I can use Gigabyte's System Information Viewer software to set the various system fans to a particular speed, but the blue temperature 'dot' does not move up and down the curve like the CPU and CPU_OPT fans do, so the software does not help. The 3rd party software Speedfan does not detect my fans, which may be due to it being a relatively new board, or perhaps whatever is causing the issue at a system level is blocking it.

I have tried multiple BIOS versions to see if that helps but the issue does not change.

Can someone confirm that the system fan speeds should be automatic based on temperature? At this point I'm thinking there's something wrong with my particular motherboard and I'm considering returning it.

Any help would be greatly appreciated.

Thanks.

[dmdilks]

How much does the temp change in the case? If the case temp doesn't change that much the system fan will not either. How many fans are you running? If you disconnect all the fans but the one at the back of the case. Then you might see a change.

If you are getting enough cool air coming or going the fans will not speed up. Those fans are base on the temp in the case. When you connect them to the CPU header they will work off the temp of the CPU.

[GurtTractor]

I did not realise that the system fan's speed was derived from the system temperature... I did some testing and it seems they change based on the TMPIN0 reading in HWMonitor. I don't know where that sensor is on the board exactly, but I guess it's not near the CPU. I totally missed the fact it said system rather than CPU in the manual, it should probably be bolded so that people such as myself are less likely to be confused. I can now set a sharp curve within SIV for the system fans, and I can continue to have the two top fans controlled by CPU_OPT to blow air across the cooler under load, which works well.

I'm very glad I don't have to return the board, thank you for the help!