seriously go look up you tube videos about how loud it can get
And that's the worst case, they're better as a case fan or on the air cooler heatsink. That said, my first impression of regular MLs when they came with my AIO was that they're somewhat loud, i've swapped them with NB eLoops but didn't revisit them since them, i need to find them somewhere in the hardware pile and retest...
That, and again, Corsair ML/ML Pro and the fan in RM-x 2021 are different, they have different impellers, that's the most important part of the fan, general purpose fans for the most part are tuned somewhere in between of good airflow and good static pressure, all you need for PSU fan is as high static pressure as you can get. And, again, RM-x 2021 performs in this review as it performs not because the fan is loud (as in noise to performance) but because the RPM curve is not as relaxed as on previous version, plus as Aris mentioned in the review, when there's high load on minor rails PSU ramps up RPM even higher, skewing the average noise chart, it's really not representative of the noise output of PSU in regular conditions, you need to look at that colorful 2D graph with 12V and minor rails on X and Y axis and the noise represented as color. Also, Jon have already stated that they've relaxed the RPM curve in production, the one in the review was pre-production sample.
- update -
Additionally, the fan reviews on this very site, very meticulously made, show the same picture.
Corsair ML Pro :
Noctua P12 :
You can see that they're nearly identical for radiator use with ML actually being slightly better, only topped by Noctua A12x25 which is unsurprising, it's a very good fan indeed.
