G1 Sniper Z170 - Fan Control Issue

[gbh4]

Hi

I've just set up a watercooled system. Everything is running ok but I'm having issue with the fan control.
I have my pump connected to CPU FAN and my 4 fans connected to SYS FAN 3, by way of an EKWB PWM fan splitter cable. In the BIOS both these connections are set to Normal mode.

My issue is that the fans connected to SYS FAN 3 are running at full speed and nothing I do can change that.
I've installed System Information Viewer and can do a custom setting for the pump on CPU FAN and that works fine and changes speed correctly, but changing the same settings for SYS FAN 3 does nothing at all.

I've tried Speedfan and that doesn't detect the CPU FAN or the SYS FAN 3 connection.

Any ideas what to do? I'm guessing it's some setting in the bios perhaps?

[gbh4]

An update on this.
I have now done away with the splitter cable and have all 4 fans connected to the fan headers.
The fans are Corsair HD120 RGB and all have 4 pin connectors.

Using System Information Viewer I can now change the speed of all the fans and have setup a custom curve to suit. BUT, when the system restarts it doesn't load this config, even though the SIV is running I have to manually tweak the curves then click apply to engage the setting.

Also, none of the fans show up as PWM in HWMonitor and none appear at all in Speedfan.

Is there a BIOS setting I need to alter so PWM will work?

Thanks

[gbh4]

Another update! I now have SIV starting with Windows so my fan speeds run correctly.
But I still have the issue of Speedfan not detecting any fans and HWMonitor showing them as non PWM fans.

Any ideas?