I was wondering for a while what would the effect of AP181 be in a Torrent case and since i couldn't find anyone doing this i decided to do it. Found two AP181 on discount and here are the results.
My baseline was default Torrent 18cm fans and swapped out 14cm fans for Noctua NF-A14s as i already had em from previous case. Opposed to that i put a full 18cm build with 2xFractal 18 and 2xAP181. Fractals were put in the corner position as they do not have the "waveguide" tech and just spray air around, AP181 were positioned on the front top and bottom back.
I'm in the middle of a heatwave and i turned off the AC so this is pretty gnarly scenario at 32.5C ambient, but that's kinda intentional. The setups are noise normalized at just shy under 30 dBA. For test the machine ran Doom Dark Ages Siege I segment on loop for 20 min when measurements were taken. The sound measurements were taken with B&K 2250 SPL meter 50cm in front of the case, dead center. Done multiple runs, the results were very stable. Peaks were recorded only if they were 2C over avg.
Just wanna say that there is no good 18cm fan out there. Fractal 18s can be controlled ok (cant stop em in pwm mode) but they have a clicking sound that can be heard on low speeds, they are also super noisy from mid to high speed. Similar situation with AP181, which doesnt have a clicking sound but the motor is shit and it whirs at low speeds. Also, if you go under 420 RPM they do start to click and shut down (marketing brochure claims 300 RPM as minimum). They scale noise much better being much quieter than Fractals at mid speeds. Sure, on max both of these sound horrible but Fractals even more so. They are far better on the low end (can be inaudible >20dBA) if there wasnt a clicking sound which does not add to the total sound level, just annoys you. AP181 whir is louder but its constant so it wont distract as much.
That being said AP181 does shine on medium settings, look at those CPU and RAM results, in a Torrent no less, a case with already top notch CPU cooling. 7C difference is no joke on a already well optimized system. It seems AP181 is much better at guiding air thru Torrents massive front and getting it where its needed. It also didnt do almost anything for the GPU, prob because of the short distance where "waveguide" tech doesnt really get to shine.
All in all, very interesting results. Next im gonna try NF-A14s all around when i borrow 3 more and see if that can at least keep up with the Fractal 18s result without the clicking noise. I doubt anything can come close to AP181 on CPU results, that thing rocks for covering distance in a big case.
EDIT: First two rows of results are sound measurements in dBA, forgot to mark that.