Noctua NF-A12x25 G2 PWM chromax.black Fans: A Must Have for Stealth Builds

NF-A12x25 PWM G2 got our praise when we tested those fans for providing even better noise-to-performance efficiency over the NF-A12x25 PWM fans. Noctua is good at gaining from the learning curve, as it has released the chromax.black version of the NF-A12x25 PWM G2 fans.

As we mentioned in the review of NF-A12x25 PWM G2, Noctua aims at the mid-section of the P/Q chart, i.e., trying to achieve the best optimal combination of air flow and air pressure. The NF-F12 fans favor the air pressure applications in particular, and not all scenarios require such applications. The fan sitting in the mid-section provides a good all-round performance for your particular PC related cooling requirement. This was made possible with NF-A12x25 PWM fans and now with the further refined and well-tuned G2 version.

These fans are available in 2 options:

• NF-A12x25 G2 PWM chromax.black Single Fan Pack costing Euro/USD 34.90
• NF-A12x25 G2 PWM Sx2-PP chromax.black Two Fans Pack costing Euro/USD 64.90

The S-2xPP fans come with two NF-A12x25 G2 PWM chromax.black fans operating at an offset speed to reduce harmonic phenomena like intermittent vibration or humming coming from interference. This offset is ±50 RPM.

Specifications

Packaging and Contents

The fans are shipped inside cardboard packing boxes. The black color scheme tells you that these are chromax.black variants, otherwise it would be a tan and brown color scheme. The Sx2-PP chromax.black fans come in a large-sized packing box. These fans are placed parallel to each other in this box, and there is an accessory box between the fans. The single fan pack comes with an NF-A12x25 G2 PWM chromax.black fan and an accessory box. All editions have standard accessories.

The NF-A12x25 G2 PWM Sx2-PP chromax.black box comes with

• 2x NF-A12x25 G2 PWM chromax.black fans
• 2x NA-RC7 Low-Noise Adaptor (L.N.A.)
• 1x NA-YC1 4-pin PWM splitter cable
• 2x NA-EC1 30cm extension cable
• 1x NA-AVG1 anti-vibration gasket
• 4x NA-AV2 anti-vibration Mounts
• 8x Fan screws

Closer Look

The new generation NF-A12x25 G2 PWM chromax.black fans are designed on the building block of NF-A12x25 PWM, hence they carry the same technologies and design as the NF-A12x25 but with further enhancements. They are the black versions of the regular NF-A12x25 G2 PWM fans, hence nothing is changed except the color. Expect similar performance characteristics on these fans as on the regular fans.

There are plenty of key notes when it comes to the design of NF-A12x25 G2 PWM chromax.black fans, which is obvious given they follow the design of NF-A12x25 PWM in that sense. Each fan has 9x impellers. They are progressive bend impellers featuring flow acceleration channels and winglets.

These blades are swept backwards close to the hub and progressively bent forward further out. These work in tandem with the centrifugal Turbulator hub to improve the lift and uniform loading across the blade surface.

The winglets are introduced in an attempt to reduce the tip vortices. The NF-A12x25 G2 PWM chromax.black’s winglets are fine-tuned to work with other features of the frame for consistent efficiency.

Noctua has used LCP (Liquid Polymer Crystal) material for the impellers, as we saw on the NF-A12x25 PWM fans. Noctua was the first brand to start using LCP and ultra-low tip clearance, with others following in the same design footprint.

Noctua is using the same AAO (Advanced Acoustic Optimisation) frames that are on the NF-A12x25 PWM fans. These frames use integrated anti-vibration pads, Noctua’s proprietary Stepped Inlet Design, and Inner Surface Microstructures. All these work together to provide the best possible performance and reduce noise output.

These fans come with 4x load-relief anti-vibration pads pre-installed on the front side of the fan. The rear of the fan also comes equipped with these pads, unlike the NF-A12x25 G2, which has a NA-AVG1 silicone gasket installed on the rear of the fan out of the box. However, Noctua has provided this gasket in the accessory box, should you want to use it. This gasket is useful for radiator and surface mounting, providing a tight seal with the fan.

Since gasket covers the entire border of the fan’s frame, it helps to damp vibrations and to reduce air loss between the fan and the radiator for optimal cooling performance. The Anti-vibration pads serve a similar purpose.

Noctua branding is visible on one side of the main frame.

The two arrow markers on the other side of the main frame provide a visual guide to the user. These show the direction of airflow through the fan and the direction in which the blades spin.

The backside of the fan has an inward slope on the four sides. There is a 4-arm assembly connecting the motor hub with the frame. The fan draws 0.14A at 12VDC using 1.68W of power. The arms are angular, providing directional airflow.

The NF-A12x25 G2 PWM chromax.black fans use optimized SSO2 bearings in which the rear magnet is placed closer to the axis for stabilization. Noctua has employed a CNC-milled bearing shell made of brass material, providing long-term stability with minimum tolerance.

Noctua has used the NE-FD6 motor drive system in these fans, which is combined with the SupraTorque technology. This motor provides better energy efficiency. This motor has a Hall Effect sensor for precise commutation performance. Speaking of commutation, these fans have Noctua’s Smooth Commutation Drive 2 technology. The aim here is to reduce the motor noise to the extent possible.

The SuporaTorque technology allows these fans to maintain the same RPM even when employed on the surface with high back pressure.

You can use the NA-IS1-12 inlet side spacer with the NF-A12x25 G2 to reduce influx turbulences in “pull” type applications where the fan draws air through a grill, mesh filter, or perforated panel.

Noctua has managed 0.5mm tip clearance between the blades and the frame. This design helps in reducing leak flows through the gap between the blades and frame. This would improve the performance efficiency even with high resistant surface.

The functionality of coming to a stop at 0% PWM gives these fans a huge lift for the semi-passive cooling application. In addition, the wider PWM range goes from 360 RPM to 1800 RPM.

Safety Data

These fans come with safety features/protections that include:

• Reverse Polarity Protection
• Over Voltage Protection
• Over Current Protection

These protections make these fans suitable even in challenging electrical environments. You can have peace of mind.

Testing

The following configuration is used for thermal testing:

• AMD Ryzen 9 9900X
• ASRock X870E NOVA WiFi
• GSkill TridentZ NEO RGB 32GB 6400MHz CL30 DDR5 kit
• DeepCool LT360 Vision ARGB Liquid Cooler
• ASRock Phantom Gaming RX 7600 Graphics Card for Display
• Biwin Black Opal X570 Pro 4TB NVMe SSD
• Be quiet! Straight Power 11 850W Platinum PSU
• Praxis Wetbench

Here is the settings table for testing:

Settings	PBO Enabled [243W]
Clock (MHz)	Auto
Voltage (V)	Auto
Thermal Paste	Noctua NT-H2
Thermal Paste Application	Dots Method
Test Run Time	30 minutes
Idling Time	10 minutes
All Fans Speed	100% PWM Duty Cycle
Pump Speed
Stress Software	CINEBENCH R23.2
Monitoring Software	HWINFO64

I am reporting absolute temperature in the graph because the room temperature was at 25°C throughout the day. The testing is done on an open-air bench system. Once inside the chassis, the temperatures are expected to rise and would largely depend upon the optimal airflow inside the chassis.

As you can see, the Stock fans on the DeepCool LT360 and Noctua NF-A12x25 G2 PWM chromax.black fans offer similar thermal performance, but the main difference comes from the overall noise output. The DeepCool fans did 40 dB(A), which is too good, but Noctua achieves the same performance while operating at 37.9 dB(A), which is excellent. I did not feel the need to do noise-normalized testing given the noise-to-performance efficiency out of the box on these fans.

Conclusion

Noctua has released the chromax.black version of its next-gen high-performance fans NF-A12x25 G2 PWM. The new fans are available in two editions. The two-fan edition named Sx2-PP comes with two NF-A12x25 G2 PWM fans set to operate at an offset speed of ±50 RPM to overcome the humming and turbulence that may come with both fans operating at the same speed. A single fan edition of regular NF-A12x25 G2 PWM chromax.black fan is also available on the market.

The building block of NF-A12x25 G2 PWM chromax.black fans is from NF-A12x25 PWM fans, but with further enhancements in the design and technologies. These fans still use the same Liquid Polymer Crystal (LPC) material for blades as are on NF-A12x25 PWM fans.

There is nothing much to write about the chromax.black edition since it is a black version of already covered NF-A12x25 G2 PWM fans; everything else is the same. Hence, I am not going into the details of the technology and design of these new fans. I am going to list them below. You can read the content for more details, and can even find more details on the Noctua website:

• AAO (Advanced Acoustic Optimization) Frame
• Stepped Inlet Frame
• Inner Micro Structure
• Sterrox material derived from LCP (Liquid-Crystal Polymer) used on the impeller
• Gap of only 0.5mm between the impeller and the frame
• An additional brass structure to reinforce the axle mount
• CNC milled bearing shell
• Flow Acceleration Channels and Winglets on the blades
• Further improved SSO2 bearing
• etaPERF Motor with NE-FD6 Motor IC
• Commutation Drive 2 System
• SupraTorque
• PWM Regulation with auto stop function on 0% PWM
• Safety Protections for Challenging Electrical Environments
• 6-Year Warranty
• Low Noise Adapter and Extensive Cabling Options
• Integrated anti-vibration pads and gasket
• Progressive-Bend Impeller
• Centrifugal Turbulator Hub

Now, jumping to the thermal and acoustic testing, I have tested these fans on the DeepCool LT360 Vision ARGB cooler. I have already praised the overall performance of the fans on this cooler. It is not a surprise to me that the DeepCool fans and the new Noctua fans offer similar thermal performance, but the main difference comes from the overall noise output, where Noctua is unrivaled. The 40 dB(A) on the DeepCool vs the 37.9 dB(A) on Noctua fans is self-explanatory. My conclusion remains the same. If you have NF-A12x25 PWM or its chromax.black version, you are still covered well, and there is no need to upgrade to the G2 version, but if you are in the market looking for new high-performance fans with an excellent noise-to-performance ratio, Noctua NF-A12x25 G2 PWM chromax.black fans are the prime candidates, if you can pay the steep price.

Pros

• Thermal Performance
• Noise
• LCP Material
• 0.5mm Tip Clearance
• An additional brass structure to reinforce the axle mount
• CNC milled bearing shell
• Flow Acceleration Channels and Winglets on the blades
• Further improved SSO2 bearing
• etaPERF Motor with NE-FD6 Motor IC
• Commutation Drive 2 System
• 6-Year Warranty
• Black Edition

Cons

• Price