Noctua NF-B9 v Gelid Silent 9 as a CPU fan

[Mr Spocko]

I was using a Noctua NF-B9 for the TX-3 CPU cooler on my own PC..
When I got a few of the Gelid Silent 9's in I did some experiements with both fans.

The results surprised me completely.
I was initially a bit concerned the Noctua was not that quiet (at full speed) which is around 1600rpm which is not hugely fast for a 92mm fan
The Gelid is rated at 1500 rpm both were slightly different real world max speeds with the Noctua a bit faster (it's a tad under 1700 at full speed) the Gelid was just over 1400rpm which is in line with the +/- 10% most makers put out spec wise.

But Noctua claim the B9 is 17.6 dBA and Gelid say the Silent 9 is 20. Even matching speeds as close as I can rpm wise the Noctua is def louder than the Gelid absolutely no questions..and I've a few samples to try same result...at full speed the Noctua is disappointingly noisy the Gelid is not silent but significantly quieter at the same rpm. I spent a few hours doing some of my own tests and the Gelid was able to deliver better cooling on the TX-3 cooler at a much lower rpm than the Noctua..so for example the Gelid was at around 550rpm the Noctua was at about 850rpm and I got temps that were identical. So that sealed the deal for me I won't be buying any more Noctua B9's it's a disappointing fan noise wise and for use as a CPU fan. It's acceptable if you're using it at lower rpm's it's fairly quiet at 1000rpm but what's the point when the Gelid is cheaper and bettter in every way.

I still like the 120mm ULN Noctua case fans but it's put a downer on Noctua because I simply don't think fans like the B9 are worth the money nor are they that quiet/good airflow or static pressure wise. It's a nice thing to think you can spend more get more, in this case spend less get more is the order of the day!
Despite the fancy packaging and fan blade design it's inferior to a fan costing 1/3 of the price.

I've swapped out my fan with the Gelid Silent 9 I'm pretty impressed with this fan it's quiet, has good staic pressure and airflow the 5 year warranty helps seal the deal. Whilst I don't have any audio testing equipment to measure noise I'm of the view that Noctua's numbers are simply not accurate for noise.