Visual inspection
The NF-A12X25 LS-PWM is virtually identical in design with the regular NF-A12X25 and of its counterparts. The fan uses the same nine impeller design with the same SSO2 bearing system.
The only difference between the NF-A12X25 LS-PWM and the other variants is the speed. The NF-A12X25 LS-PWM has a maximum speed of just 1200 RPM, because this fan was made to be used on the NH-P1 passive CPU cooler, and thus, was made to be as silent as possible.
The main feature of this fan and the entire NF-A12X25 series is the usage of the Sterrox polymer which allows the fan to have a smaller clearance between the blades and the frame. A smaller gap between those two components means less static pressure leakage and a better performance overall.
The fan has nine impellers, and each of them has a curved design among other features meant to improve the performance of the fan. Another feature present on these impellers is the Flow Acceleration Channels. The main purpose of these is to increase the speed of the airflow and reduce the vortex noise.
The NF-A12X25 LS-PWM, just like its counterparts has a small gap between the tip of the impellers and the frame. The gap is 0,5mm and it will prevent air flow and static pressure leakage and thus, help the fan deliver a better static pressure and airflow.
The bearing used on the NF-A12X25 LS-PWM is the Noctua SSO2 system. This is one of the best bearing systems available on the market, as it’s not only proven to be reliable but also quiet even after constant operation. The hub and motor assembly of the fan are made from plastic and metal.
The corners of the fan frame are covered by good quality rubber pads on both sides. This is done to not only prevent the fan from scratching the surface it sits on but it will also reduce the vibrations of the fan.
The back of the fan has the standard number of beams which support the rotor assembly. The back of the fan hub features the classic label with the model number, input power and input current.
The NF-A12X25 LS-PWM uses a standard 4 Pin connector for its power delivery. The cable is covered by a high-quality sleeving which is flexible.
Love the low PWM threshold, it’s super quiet, slightly audible at 80% and more. But it moves a lot of air at 40-60%. Used it with Noctua’s passive NH-P1 cooler on my AMD 5950x. It works very well, doesn’t really need to come on except during heavy workloads. Even though the P1 cooler is not rated for the thermal load of the 5950x, I am able to get 90% of the performance of the CPU.