Our tests have shown that the Arctic PWM 4-pin 40 mm fan in combination with the Bitaxe Gamma 601 and the ArcticCore Cooling Kit achieves the best cooling performance of all tested fans – especially when it comes to significantly reducing the often critical VREG temperature .
In this test, we focus on the Arctic fan in direct comparison with the Noctua NF-A4x20 5 V PWM , which is very popular in the Bitaxe environment, to show how much potential there is in a targeted BackFan upgrade.
Why the VREG temperature is so crucial
The warmer the system—and especially the voltage regulator (VREG)—gets, the higher the power consumption due to the increasing electrical resistance. This has two direct consequences: First, energy efficiency decreases, and second, the overclocking headroom shrinks, as the Bitaxe firmware goes into emergency mode at around 45 W.
By specifically controlling temperature and clock speed, a "sweet spot" of the ASIC chip can be found in which the chip operates optimally and the miner runs stably and efficiently – just as was clearly shown in the ArcticCore test.
Basics & experimental setup
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Miner: Bitaxe Gamma 601
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Cooling system: ArcticCore Cooling Kit + Geeekpi Low Profile Plus cooler
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Overclocking: Frequency 950 MHz, Core Voltage 1270 mV
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Compared fan variants:
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Noctua NF‑A4x20 5V PWM (Reference)
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Arctic PWM 4-pin @ 5 V
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Arctic PWM 4-pin @ 12 V
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Test conditions: Identical environment, measurement procedures and manufacturing.
Technical highlights of the Arctic PWM 4-Pin 40 mm
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Fan size: 40 × 40 × 28 mm
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Weight: 42 g
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Speed: 1400–15,000 rpm (controlled via PWM in 12 V operation)
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Airflow: 19.23 cfm | 32.67 m³/h (in 12 V operation)
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Static pressure: up to 26.5 mmH₂O
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Starting voltage: 4.5 V – operation from 5 V possible without any problems
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Current & Voltage: 0.47 A at 12.0 V DC
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PWM connector: 4-pin
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Cable length: 40 cm – sufficient for direct connection to the Bitaxe
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Bearing: Japanese double ball bearing for durability
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Warranty: 6-year Arctic manufacturer's warranty
Measurement results in comparison
| fan | Power (W) | ASIC temperature (°C) | VR Temp (°C) |
|---|---|---|---|
| Noctua NF‑A4x20 (5 V PWM) | 35.7 | 53.6 | 56 |
| Arctic PWM 4-pin (5 V) | 35.3 | 53.4 | 51 |
| Arctic PWM 4-pin (12 V) | 34.9 | 52.0 | 47 |
(All tests under identical performance and environment)
Analysis of the results
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Noctua (5 V): Proven stability, but highest VR temperature.
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Arctic (5 V): Slightly reduced ASIC temperature, significantly cooler VREG (-5 °C) , with slightly louder noise level than the Noctua.
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Arctic (12 V): Best cooling performance, but considerably louder – only useful in a separate setup and not in the living room. VREG (–9 °C) cooler.
Available now
The tested Bitaxe BackFan Upgrade – Arctic PWM 4-Pin 40 mm can be found here:
👉 Go to the product in the shop
Perfectly suited for 5V operation on the Bitaxe Gamma 601 and easy to install – for more stable temperatures and longer hardware lifespan.
Note on 12 V operation
The Arctic PWM 4-pin supports both standard 5 V and 12 V operation. While the 12 V mode delivers maximum cooling and achieves optimal temperatures, it is significantly louder , making it unsuitable for use in residential spaces. For silent setups or indoor use, we believe 5 V remains the recommended option.
Note for dual fan operation
To operate a second fan on the rear with the Bitaxe Gamma, a PWM fan hub is required.
Practical example: PWM fan hub on Amazon
Conclusion
The Bitaxe BackFan Upgrade – Arctic PWM 4-Pin 40 mm is a well-considered, efficient improvement over the standard setup. Especially in 5 V operation, it offers noticeable relief for the VRG, while remaining quiet – ideal for more efficient home mining. Those seeking maximum performance can cool even more deeply in 12 V mode – but will have to compromise on noise.
Safety notice
All modifications and overclocking measures are performed at your own risk – correct configuration, cooling, and operational safety are the responsibility of the user. Improper interventions can cause damage. The measured values are system-dependent – deviations due to environmental conditions, airflow, or individual ASIC characteristics are possible, as already emphasized in the ArcticCore article.
