More pressure. More air. More power for your Bitaxe Gamma.
The Bitaxe BackFan 40 mm brings a high-performance fan, the Arctic S4028, to your Bitaxe – with strong static pressure, high efficiency, and controllable PWM mode. A noticeable upgrade to the Noctua NF-A4x20 5V PWM.

12 V fan, also usable with 5 V:

The Arctic fan is designed for 12 V, but runs seamlessly on 5 V directly via your Bitaxe's fan connector—including PWM control. This provides significantly more airflow and static pressure—ideal for targeted cooling of the VREG on the rear.

Note: In 5 V operation, the fan is slightly louder than the Noctua NF-A4x20 5V PWM. In 12 V operation via an external fan controller, it reaches full performance, but is significantly louder – therefore, continuous use at 12 V in living spaces is not recommended.

Technical highlights:

• Fan size: 40 × 40 × 28 mm

• Weight: 42 g

• Speed: 1400–15,000 rpm (controlled via PWM in 12V operation)

• Airflow: 19.23 cfm | 32.67 m³/h (in 12V operation)

• Static pressure: up to 26.5 mmH₂O

• Starting voltage: 4.5 V – operation from 5 V possible without any problems

• Current & Voltage: 0.47 A at 12.0 V DC

• PWM connector: 4-pin

• Cable length: 40 cm – sufficient for direct connection to the Bitaxe

• Bearing: Japanese double ball bearing for durability

• Warranty: 6-year manufacturer's warranty
  
  

Scope of delivery:
Everything you need for your upgrade – included in the set:

• 1× Arctic S4028 fan (40 × 40 × 28 mm, PWM, 4-pin)

• 4× mounting screws (M3 × 35 mm, suitable for Bitaxe Gamma mount and bitcooler ArcticCore mount)

Why this fan?

• ✔️ Powerful at 5 V – ideal for Bitaxe Gamma

• ✔️ PWM controlled – full control over speed & temperature

• ✔️ More pressure than Noctua NF-A4-20 – better airflow for the VREG

• ✔️ Robust & durable – even in continuous operation