4-pin 120mm x 38mm

Lift off. Scary fast. I would only use this at full speed for seriously heavy duty work. It is super fast but also super loud! Not suitable for home or office environment running at full tilt. As others have stated, it is like a vacuum cleaner - beside you! Imagine that for a couple of hours. Don't get me wrong, it definitely does the job well but consider this. The fan is solidly built and the blades are thick. Minimum vibration, maximum airflow. All this is what makes the noise - it is actually the movement of the air. And has also been stated by others don't be clever and connect it before adding the grille and installing it, you could lose a fingertip and if a blade snaps off an eye also. Please observe this - also stated in the accompanying leaflet. As it is PWM not Molex socket you can adjust the speed and is much quieter when running slower. Another point to consider is the depth - much deeper than other fans so make sure you have the space and headroom. The long screws also have little nuts to help secure it. Last point is my PC won't run it at max speed. It gives a short burst of max then drops to about 60% and continuously cycles like this. I'm sure if I tweaked the voltages I could get 5300rpm but that itself will generate more heat and I am not tweaking my mobo any more than I have to. IMHO a fan does not warrant this so I'm leaving as as and have found the sweet spot of 86% as max (approx 4800rpm) -more than enough, but still loud!

I bought these to replace the fans in my Supermicro rack, thinking that after adjusting the speed, they would be quieter than the standard Supermicro fans, which sound like an A380. I was wrong... these sound like a C130! They definitely work well in terms of airflow, are value for money and are of a high build quality but, IMO, are not suitable for most home servers, unless you have it in a soundproof cabinet or the rack itself has robust sound proofing.

Very good with airflow but wouldn't put it on a splitter as needs it's own header to power, little noisy but I have mine running at full power so is understandable, plus would depend where you place/mount the fan as to if the noise would be an issue.

noisy and strong, sound is over 100DB

Very powerful small fun. Noisy too. But if you need cooling your device fast, that should be perfect for you.

Used with my k80 Tesla card. Good little fan, yes.

This fan has both high static pressure and passes a larger volume of air, man does this blow!!!!!!! I got this for my 100Watt LED heat sink, the heat sink does not even get a chance to warm up with this fan on!!! Only slight negative it is a bit loud but not excessive. This is prefect for what I am using it for.

This 12V 80x38MM 4 pin Delta Electronics fan does its job fine it pushes out a heck of a lot of air at full speed I've got it hooked up to a LiFePO4 battery by splicing a cig socket cable to the red/black cables with the fan spinning at just over 6000RPMs. I don't mind the fan noise at all I actually like it a lot but I can see it annoying many people as it is fairly loud and sounds like a jet before takeoff. I'm currently using this with several small electronics projects by using a single channel fan controller to control the voltage via a resister. The only negative about this model is I don't think it can start up at 5V even if you give the blades a prod as some of my crazy airflow 80MM and 60MM delta fans run fine at 5V even at 4.5V if you give the blades a prod before applying power but for the RPMS of this fan I could probably get away with pushing 7.5V through it. This uses standard 4 pin wiring so no guessing what each wire does which is nice unlike my crazy server fans which use odd colour combinations. I'l use this as a portable room cooler in the summer and to cool down cups of tea etc as its very portable so 5 out of 5 it would be good if the price was a bit cheaper but you can't have everything.