Noctua NF-A4x20 Silent Fan

The Noctua NF-A4x20 is a PWM fan measuring 40 × 40 × 20 mm and goes exactly where boards such as the Bitaxe Gamma carry a 40 mm fan from the factory. It runs at 5 V through the existing 4-pin connector, so your miner’s fan curve controls it just like the original – no adapter, no firmware changes.

At 14.9 dB it is the reason a miner moves from the shelf back onto the desk. Its 0.5 W of consumption is negligible next to that: at an electricity price of €0.28/kWh the fan costs around 10 cents a month.

• Calmer running: 14.9 dB and an even tone instead of bearing hum. What remains audible is mostly the airflow.
• Fits without modification: same 40 mm frame, same 4-pin plug, same 5 V. No soldering, no adapter cable.
• Control is preserved: speed readout and fan curve work after the swap exactly as before.
• No cost factor: 0.5 W at 5 V changes your running costs practically not at all.

What matters is the 40 mm frame. That makes the fan fit the mounts of the Bitaxe Gamma, Bitaxe Copperzilla, Nerdaxe Gamma and Nerdaxe Gaia, all of which ship with a 40 mm 5 V PWM fan.

Watch the 20 mm height: the NF-A4x20 is a thick 40 mm fan. In an open build that is irrelevant, but in a tightly cut case or above a tall tower cooler it can get close – check the space there first.

For everyone who runs their miner in a living room or office and sees the noise as the actual problem. If you run moderate settings anyway, the swap mostly does one thing: it gets quiet.

It is less suitable at the temperature limit. Customers say it openly: the Noctua moves slightly less air than the loud stock fan. If you run high clocks permanently, you gain quiet and lose headroom – then more cooling surface is the better step.

A screwdriver and a few minutes: undo the old fan, unplug it, plug in the new one and screw it down. Check the cable route while you do – customers report it gets tight when the header sits far away. Afterwards check fan speed and ASIC temperature in the web interface.

• ICE Tower Kit: more cooling surface so the quiet fan may spin slower.
• Noctua NF-A6x15: the 60 mm sibling for boards and cases with a larger fan mount.
• Cooling for heatsinks and kits that catch the heat before it reaches the fan.

The NF-A4x20 is the smallest sensible upgrade on an open-source miner: one component, a few minutes of work, and the device is allowed to stand where you work. It changes nothing about hash rate – and a lot about living with the miner.