Noctua NF-A12x25 G2 PWM High Performance Fan Review

Back in the early days of Ninjalane I didn’t care too much about fans, they spun, they made noise and the crappy ones would soon become noisy and promptly replaced.  The usual culprit was bearing failure that could be addressed by adding a drop of oil to the bearing.  This had always been a temporary fix but, was one way computer modders would salvage their systems.  Errors like this created a land rush in the computer hardware world where some companies would take the issue seriously while others tended to do whatever was the cheapest to avoid the costly tooling required. 

As you may have guessed many companies opt to solve the immediate issue because it can deliver a quick return with very little effort.  This often creates designs that do nothing but expose the next weakest link.  For instance, you may get a fan with good bearings but inefficient blade profiles or, fans with overpowered motors do nothing but generate noise. 

Often the difference between a good product and a great product is the elusive 20%.  It is easy to create something quick and get it 80% complete but then fail to deliver on the most difficult 20% to actually complete the project.  In this review we will be looking at the Noctua NF-A12x25 G2.  This fan is not a new design, the 140mm edition was released a year ago with the launch of the Noctua NH-D15-G2. 

When speaking with Noctua I was told that every product they build is unique.  While the design for the 140mm G2 is virtually identical to the 120mm G2 there was almost a year between the two releases to ensure that this fan was thoroughly tested with every manufacturing problem resolved to the highest level.  Normally the 120mm fan would be released first however, with the shift in case design and growing popularity of the 140mm fan many companies have started to shift their efforts to meet the needs for market demand.

To help illustrate the quality of the Noctua NF-A12x25 G2 here are some close-up shots of the frame showing the dimple pattern and the tolerance between the fan blades and the frame. 

These two features do more to increase airflow efficiency and lower noise than most anything else you can find on the market today.  Thing is, building a fan of this quality takes a long time and requires the right combination of materials to work.

Much like with the 140mm version that comes with the Noctua NH-D15-G2 the major difference is the blade design.  Starting at the center of the fan you will find several low profile vanes that help to move the dead air around the fan hub and increase airflow.  The blade design is also very unique in that it will direct airflow naturally into a column without the need of focus flow fins.

As with any axial fan, the exhaust air is forced out and away from the fan center due to centrifugal force.  The focus flow fins redirect this air based on the position and angle of the fins, turning a cone of air into a column.  Curved fan blades tend to do the same by preventing air from leaking outwards and forcing it back towards the middle.

To help show the different design philosophies I have three popular Noctua fans.  To the right is the NF-F12 featuring the focus flow fin design.  This fan is nearly fourteen years old and is still one of the best radiator fans I have ever used.

At the top is the Noctua NF-A12x25 and was released in 2018 and quickly became one of the smoothest fans I have ever used.  This design was virtually silent at all speeds, offered extremely good flow and pressure while removing the need for the focus flow fins.

What I find ironic is that, the NF-A12x25 was copied by almost every fan maker, with some designs actually being pretty good. 

The G2 in the lower left takes the design one step further by tweaking the blade design to have more surface area combined with a unique shape.  This forces the trapped air to exit near the center of the blade instead of near the hub.