PWM fan control

Canary Wundaboy · 15 Apr 2021 at 16:17

Hi All,

I bought a Corsair 5000D case to replace my ageing NZXT Phantom 410. In my old case all the fans were plugged into extenders that hooked up to a control board, that was controlled by a manual switch on the top panel. Slide the switch down and the fans spin slower, slide it up and they go full pelt.

With the new case, it comes with a PAWM board that needs power, and then connects to the motherboard. No bother, I've hooked it up to a SATA power connection and SYSFAN_1 on my motherboard (a Gigabyte Z97 Gaming 7).

The problem is, how do I now control the fan speed? They're all running full pelt and I can't figure out how to slow them down. I don't know whether I need Corsair software, I've tried the Gigabyte "System Information Viewer" and that doesn't seem to have sensed the presence of the fan control board. Also all my fans are 3 pin, but the control board male pins are 4-pin, if that means anything?

Cooler running · 15 Apr 2021 at 18:43

Can't speak for Corsair stuff, but my "be quiet" case has one of those fan hubs. In my case there is a little switch on it that toggles between preset speed and PWM control. There is a cable coming off of the fan hub which accepts the PWM input.

Canary Wundaboy said:
Also all my fans are 3 pin, but the control board male pins are 4-pin, if that means anything?

PWM fans are 4 pin, DC fans are 3 pin.

Did the 3 pin fans and hub come with the case?

From what I understand you can adjust the speed on 3 pin fans via the voltage, so either the hub is not able to convert the PWM input to 3pin voltage, or you just have it setup wrong. I assume if the fans came with the hub that it would all be fine and you just had to set it up differently.

Canary Wundaboy · 15 Apr 2021 at 19:09

Ah, so my fans are all 3 pin ones, not 4. The connectors on the board are 4 pin, as is the connection from the board to my motherboard. The fans that came with the case were 4 pin ones. I’m guessing that I have DC fans. What implications does that have for fan control. I plus I be better off looking at someone like the commander pro unit to control these fans independently or do I need to replace all my fans?

LePhuronn · 16 Apr 2021 at 10:17

Can you clarify which fans you're using? Are you using the fans that came with the case, or have you replaced them?

In either case, fan control can be done through the BIOS. Should have a few presets to determine how the fans ramp up with temperature, or you can set a custom fan curve (BIOS permitting). I suspect the fan board you mention is just a dumb splitter rather than something to provide additional channels, so all fans attached to it will be treated as a single fan on whatever motherboard header you use.

If you want to control the fans independently, then you'll need a proper fan controller.

The only thing now is whether you set up fan control in the BIOS as PWM control (if you're using 4 pin fans) or voltage control (if you're using 3 pin fans). But do make sure you select the correct one; PWM control on a 3 pin fan does nothing (no 4th wire to send the control signal) and voltage control on a 4 pin fan can make them sound rattly and grindy at lower speeds because the motor is designed to run at 12V all the times.

Canary Wundaboy · 16 Apr 2021 at 23:56

LePhuronn said:
Can you clarify which fans you're using? Are you using the fans that came with the case, or have you replaced them?

In either case, fan control can be done through the BIOS. Should have a few presets to determine how the fans ramp up with temperature, or you can set a custom fan curve (BIOS permitting). I suspect the fan board you mention is just a dumb splitter rather than something to provide additional channels, so all fans attached to it will be treated as a single fan on whatever motherboard header you use.

If you want to control the fans independently, then you'll need a proper fan controller.

The only thing now is whether you set up fan control in the BIOS as PWM control (if you're using 4 pin fans) or voltage control (if you're using 3 pin fans). But do make sure you select the correct one; PWM control on a 3 pin fan does nothing (no 4th wire to send the control signal) and voltage control on a 4 pin fan can make them sound rattly and grindy at lower speeds because the motor is designed to run at 12V all the times.

I have Corsair AF120 fans throughout, replaced the 2 4-pin ones that came with the case (boring black one) as the AF120s have red leds. They’re all 3-pin. I ended up buying a Corsair Controller Pro and just installed it this evening, works a treat!