Arctic S4028-6K Server Fan 40x40x28 Dual Ball - ACFAN00185A

The Arctic S4028-6K is a small but serious 40 mm fan, primarily aimed at servers, networking equipment, and tight cases where space is critical. With dimensions of 40 x 40 x 28 mm and a high maximum speed of up to 6000 RPM, it is designed to push air through dense radiators, grilles, and chassis. The dual bearing (2 Ball Bearing) is a big plus for 24/7 operation and installation in any orientation. There is no RGB, it is entirely black, and it is clear that the focus here is on functionality and reliability, not aesthetics.

What you get

The fan operates in a wide range of 250 to 6000 RPM, giving you flexibility – from quieter operation at low speeds to aggressive cooling when the system is under load. The airflow of 7.1 CFM may seem modest on paper, but at this size and a maximum static pressure of 4.2 mmH2O, it is ideal for tight channels and dense radiators. With 12 V power and a 4 PIN connector, you can connect it to a standard motherboard connector for PWM control, allowing you to adjust the speeds according to temperature. The low current of 0.1 A means that the load on the power supply is minimal, even if you use several such fans in one system.

• Compact form factor with dimensions of 40 x 40 x 28 mm, suitable for server cases, networking devices, and other tight spaces.
• Wide range of 250–6000 RPM, allowing both quiet mode and aggressive cooling when needed.
• Airflow of 7.1 CFM, optimized for small diameter and effectively directed cooling.
• Maximum static pressure of 4.2 mmH2O, helping air pass through dense filters, radiators, and grilles.
• 2 Ball Bearing bearing, ensuring long life and reliable operation under 24/7 load and any orientation.
• 4 PIN connector for convenient speed control through motherboards or controllers, without the need for additional adapters.
• Low current of 0.1 A at 12 V, which spares the power supply even with multiple fans in one system.

Who it is suitable for

This fan is a good choice if you are assembling or servicing a server, router, firewall, NAS, or compact industrial machine where you need a small but reliable fan with high RPM and static pressure. It is not aimed at classic gaming cases and RGB builds – it is more suitable for those who think about airflow, uptime, and 24/7 operation, rather than aesthetics.

The strongest combination here is the small form factor, 2 Ball Bearing bearing, and high static pressure at up to 6000 RPM, backed by a long warranty of 72 months – exactly what you are looking for in a serious, reliable system.