The new 4-pin fans aren't functioning, while the 3-pin ones are working.
The new 4-pin fans aren't functioning, while the 3-pin ones are working.
Your new 4-pin fans are here, but the fan splitter isn’t working with them. The splitter only supports the 3-pin version you’re using, so it’s not compatible. Try connecting one fan directly to the system—without the splitter—and see if it spins. If not, consider using a 3-pin splitter or checking the fan’s specifications.
A520 refers to the chipset, not the precise model of your M.2 slot... such as the Gigabyte A520 Aorus Elite (rev 1.0)... Make sure you go into your BIOS and verify the setting for the sysfan 1—whether it's DC/voltage controlled, PWM, or auto. If using a Gigabyte M.2 slot, the display will look something like this:
a splitter uses one connector to send the PWM signal from the fan back to the mainboard, while the other connectors mirror the behavior of the initial fan, maintaining the same power and RPM. This makes them effectively DC-controlled. When using different fans with varying sizes or RPM ranges, each responds uniquely. Are the connections correct? Does the fan connector supply enough power for multiple fans? Usually yes. Have you used a multi-fan splitter with its own power source, such as a SATA port? It typically only sends the signal from the first port and draws minimal power. Overloading the fan ports can cause them to fail over time.
Discuss other configurations such as Speed Control options, manual fan settings, and the default Stop status. Also, examine the fan curve when set to manual mode. Consider disabling Stop and capture your Smart Fan BIOS settings for reference. If everything appears correct but performance remains poor with a single PWM fan and a PWM header, the header might be faulty—try a different one or check SYS_FAN 2 in the provided manual.