There are typically 4 amps in a fan header on a standard Gigabyte board.
There are typically 4 amps in a fan header on a standard Gigabyte board.
I currently use five CF120 PLUS fans on a single fan header by connecting two fan hubs together to my B550M Aorus Elite. This setup looks neat but isn’t ideal since the motherboard only has one fan header and offers two available. Even though the fans are running and total power stays under one amp, it’s not the safest or most efficient configuration. I’m curious about the amperage in a typical Gigabyte board header—since it isn’t specified on the product page or manual. Some sources say it provides two amps, but I’m not sure if that applies to my setup.
My suggestion is around one amp. Keep in mind that when connecting splitters in series, the load at the main splitter doubles for each downstream device, and so forth. You don’t have the wiring specs, so proceed with caution.
It suggests the setup might be pushing beyond the fan's maximum capacity. Since each fan draws 0.18 amps and there are multiple fans in series, ensure the total load doesn't exceed its rating. Check connections and power supply to avoid damage.
add this note that most users don’t typically operate at their full rated current. they usually hit that level only when they’re reaching 100% or starting up from lower speeds. another point is with PWM fans you can detach the +12V pin from the connector and connect it to a standard 12V line like a Molex or floppy. in fact, if you have a powered PWM fan splitter, it’s likely doing that already.
Hub 2 will deliver 0.18 amps to each of the three fans, totaling 0.54 amps in the wiring for the second hub. The first hub needs to handle a total of 0.9 amps. If the main wire from the first hub to the MBO header only supports 0.75 amps, it's being overloaded—though not impossible. It's important to consider how much current flows through the wires just as much as the components themselves. I'm not claiming you're overloading the system, but I'm just taking a careful approach. As far as I understand, you're operating at the safe limit. A simple example of approximate wire loads: Green 0.18 Yellow 0.36 Red 0.72
I should avoid connecting multiple fans to a single header because the motor's inductance creates a strong back EMF that can surge to hundreds or even thousands of volts, potentially damaging the driver. I've noticed this issue when a pump is linked to a fan connector—its larger motor winding produces a much higher back EMF than a fan, causing the driver to fail. The lesson here is clear: only use one fan per header if it's labeled as FAN.
Typical fan connectors usually carry 5 amps. My setup uses Delta AFB1212SHE rated 1.6A per header, and everything is working fine so far.