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Artikel: Fan Controller vs Fan Splitter: Which Do You Need?
Fan Controller vs Fan Splitter: Which Do You Need?
Short answer: A splitter divides the power your motherboard header already provides between more fans. A fan controller is independently powered from the PSU, so it supplies its own power and is not limited by your motherboard header. If you are only adding a second low-draw fan, a splitter is fine. If you are running high-performance fans or single-frame fan sets, you need a controller.
These two products look similar, cost very different amounts, and are not interchangeable. The distinction is simple once you see it, and getting it wrong is one of the more common ways people end up with melted cabling.
What a splitter does
A fan splitter is a passive cable. It takes one motherboard header and turns it into two, three or more connectors.
What it does not do is create power. A splitter inherits the power limit of the header it plugs into. Connect a 3-fan splitter to a 12W header and you still have 12W to share across all three fans, not 12W each.
That is the entire catch, and it is why splitters get people into trouble. Nothing about plugging in a third fan tells you that you have gone over the limit.
What a fan controller does
A fan controller is an independently powered device. It connects to your power supply directly and distributes that power to the fans plugged into it.
Because the power comes from the PSU rather than the motherboard, the controller is not bound by your board's header rating. It has its own limit, usually much higher, published either per header or as a total across the device. The NZXT Control Hub is one example.
This is what makes a controller the right answer for fan setups a motherboard cannot feed.
Side by side
| Fan splitter | Fan controller | |
|---|---|---|
| Power source | The motherboard header | The power supply |
| Power limit | Inherits the header's limit | Its own, typically much higher |
| Adds power headroom | No | Yes |
| Needs its own power cable | No | Yes |
| Good for | A second low-draw fan | High-performance fans, single-frame fan sets, high fan counts |
| Cost | Low | Higher |
When a splitter is the right call
Splitters are genuinely useful. Use one when:
- You are adding one extra fan of modest current draw.
- You have already added up the combined draw and it sits comfortably under the header's rating.
- You want both fans following the same curve from the same header, which is often exactly what you want for a pair of intake fans.
The rule is that you must do the sum first. Combined current across everything on the splitter, multiplied by 12, has to come in under the header's watt rating. Our guide to how many fans one header can run walks through it.
When you need a controller
You need a controller when the fans you want to run draw more power than a motherboard header can supply. In practice that means:
- High-performance fans such as the NZXT F120X and F140X. These move a lot of air and draw more current than standard fans to do it.
- Single-frame fan sets such as the F280X and F360X. These use one connector for what is effectively multiple fans, so the combined draw through that single cable is high.
- Motherboards with 12W headers. If your board only supplies 12V at 1A per header, you run out of headroom very quickly.
- Builds with a lot of fans. A case like the H9 Flow supports up to ten fans. No motherboard has ten headers with the power to match.
What happens if you overload a splitter
Exceeding the power limit of a splitter can result in reduced performance, or it can cause the cables to melt, damaging the header and the fans connected to it.
The failure is not always dramatic or immediate. Often the first sign is fans that never reach their rated RPM, because the header cannot deliver what they are asking for. That is your cue to check the numbers rather than to assume the fans are faulty.
Can I use both?
Yes, and it is common. A controller gives you several high-capacity headers, and you can still split one of those headers between two fans if the combined draw fits within that header's limit. The same calculation applies, you are just working against the controller's per-header rating instead of the motherboard's.
If your controller lists only a total power rating, divide it by the number of headers to get a working per-header figure. A 3-port controller rated at 72W usually supports up to 24W per header.
Frequently asked questions
Is a fan hub the same as a fan splitter?
Not necessarily, and this is where the terminology gets muddy. What matters is whether the device has its own power connector to the PSU. If it does, it behaves like a controller. If it only plugs into a motherboard header, it behaves like a splitter regardless of what it is called.
Will a splitter let me control fans separately?
No. Every fan on a splitter follows the same curve, because they share one header. If you want independent curves you need separate headers or a controller that exposes each port individually.
Does a splitter report RPM for all fans?
Usually only one. Most splitters pass the tachometer signal from a single fan back to the motherboard, so your board reports that fan's speed and is blind to the others. This is normal and not a fault.
Do I need a controller for RGB as well as fan speed?
They are separate power and data paths. On most NZXT fans, lighting has its own dedicated power line, so RGB does not draw from your fan header budget. The NZXT Control Hub handles lighting and fan control together, which is why it ships pre-installed in builds like the H9 Flow RGB+.
My fans are all running but one is much slower. Why?
Check the total draw on that header first. When a header is over its limit, fans commonly fail to reach full speed rather than failing outright. If the numbers are fine, test the fan on a different header to rule out the fan itself.
Not sure which one you need?
Tell us your fan models, how many you are running, and your motherboard, and we will tell you whether a splitter covers it. Our team is at NZXT Support.
