DB04028B12U 40mm Fan 4cm 4028 40x40x28mm 12V 0.66A Dual Ball Bearing 4-Wire 4pin PWM Server Power Airflow Coo

I purchased this fan as a replacement for the one which came with ICY DOCK ToughArmor HDD enclosure. When it comes to airflow, this little guy is an absolute beast. I was controlling it via motherboard and even though it was being run at 5V (motherboard limit), I saw speeds exceeding 13000 RPM so you can imagine the speed at full rated voltage of 12V. Now for the sad part: Even at low speed < 3000 RPM, you can't be in the same room as its distractingly loud (can't even watch a movie). When its running at full speed, its like a jet engine. I had no choice but to return it. My final verdict: As long as noise is not a concern or its installed in a secluded area at home or office, this is a great fan for the price. It will do a great job in removing heat. I can't comment on the reliability and operating - life of this fan especially when it operates at such a high RPM. High RPM does take a toll on the bearing unless they are specifically designed for it.

Blows a lot of air for the size. Used it to cool my electric motorcycle. No more overheating

Moves a ton of air but its very noisy and the blades on the intake side have pointed edges that really "bite" if you accidentally touch it while running. Be very careful while its running.

Got these to finish my ratrig vcore 4.0 projects as the factory recommended fan was rated at 25000 rim at 24v I found it way to loud and unnecessary for the speeds I'm running. This one runs at 15000 rom which is drastically more tolerable than the ones from ratrig. The balance seems good on them and I don't hear much for harmonics. Definitely recomend for normal print speed applications

Excellent fan very very powerful. Very high airflow. I run this on a 4S Lipo to cool off my RC motors.

Fan I received was a 4 wire, not PWM fan. It did not have the yellow/blue wires as expected in a PWM fan and did not operate correctly in a 4 wire PWM application.

These things move a TON of air around and are LOUD even at slowest RPM. I mean it’s like a leaf blower in a server chassis haha! They work super well for air movement and seem well made. Time will tell with that. If you want quiet move on these are not for you. But you just need some serious air flow? Buy this fan. It blows.

The thing moves a good amount of air. I'm not sure if mine was defective or not it says PWM but it always seems to run at full blast and is just too noisy. I ended up disconnecting it as it is terribly distracting, I tried altering speed but the computer doesn't even recognize it. I have a asus strix Z790e so that shouldn't be an issue the thing has multiple fan controllers. So if you need good airflow and are going to be in another room it should do fine otherwise find something that is actually controllable. buy the time I came to this conclusion the thirty days had past and now I'm stuck with it. edit the extension cable was only 2pin. I should've paid better attention but being annoyed with the noise I decided to recheck the connection was only a 2pin got proper 3pin extension am now able to control via fan xpert set a new curve I could live with, evacuates enough air to provide some small function a degree or two tops placed by gpu never checked temps under real load. but the air evacuated under moderate load is warm so I believe provides some benefit even if it is wishful thinking.