Objective of the comparison: Cooling down the 8 HDDs installed in my TrueNAS machine. The case I'm using is a Fractal Design Define R6. I installed 3x Thermalright C12 fan at the front of the case but I noticed the Toshiba MG06 drives were recording temperature of up to 58°C. I want to have my HDDs running below 50°C.

Purchased Delta FFB1212EH for rmb21/each and Arctic P12 Max for rmb57/each.

I connected to the fans to the fan hub on the Fractal Design case and it is then connected to pwm fan header on the motherboard. I set the fan speed to follow a pwm fan curve in BIOS. However, the Delta fan only seem to run at full speed.

Noise Levels (Ambient noise level 52.0dB)
Noise levels are recorded using sound meter application on smartphone next to the machine.
Delta FFB1212EH - Max 66.9dB, average 57.0dB (Video link: https://photos.app.goo.gl/4SUdk1BcrJQ8tiNu7)
Arctic P12 Max - Max 64.6dB, average 52.2dB (Video link: https://photos.app.goo.gl/jnEQv9A5SJt37W2D6)

Temperature Comparison

The graph is showing the delta of the recorded mean temperature above ambient temperature. The fans are swapped and allowed to run for more than 2 hours to stabilized the temperature recorded by TrueNAS.

Summary
Both Delta FFB1212EH and Arctic P12 Max are far superior than the Thermalright C12 fans in terms of airflow and static pressure. The weight of the Delta FFB1212EH and Arctic P12 Max clearly shows that they are using a much more powerful motor. The Thermalright C12 just doesn't have enough static pressure to blow air through the small gaps between the wall of HDDs.

In general, the Delta fans are able to cool better than the Arctic, BUT the difference is not more than 5°C and the Arctic P12 Max is running at only 0.2dB above ambient noise level. The Delta FFB1212EH are running constantly like jet engines, whereas the Arctic P12 Max will occasionally ramp up depending on the CPU temp.