![Image](https://www.silverstonetek.com/images/goods_dimension/ap183-dimension.jpg)
https://www.silverstonetek.com/product. ... undefined3
I recently replaced my Silverstone FT02B's original set of 3 9 year old AP181 180mm bottom case fans with the AP183
These are PWM, unlike the 3 speed switched AP181.
The swap required removing the AP181 fans along with their speed switches from the case
I had both fans plugged into my MSI X570 Tomahawk motherboard which has excellent fan control - both DC and PWM.
And at full speed the AP181 has more air roar, while the AP183 have more motor hum and slightly less air flow based on how much air was coming at me.
Now the Ap183 can be run at much slower speeds, being PWM, and up to 40% speed they are inaudible with an open case from 1M away.
I set my fans so they run at around 550RPM, about 30-35% speed, when my Ryzen 3800x is idling, 40-50degrees and 42% at 90 degrees.
They hit 650RPM when my Ryzen hits 70+ degrees under benching load.
Even at 500+ RPM they move a good amount of air, and are silent from 1M with an open case.
No annoying clicking or buzzes I can detect so far
Based on Open Hardware Monitor, they have run as low as 280RPM to 648RPM with my fan curve settings in Bios
I have all 3 fans plugged into the Silverstone 3 into 1, 4 pin cable adapter, and then plugged into one of the motherboard's fan header.
Each fan has 0.3 amp current draw, so safe for 1amp rated fan header
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specs are
Airflow 24.49CFM (400rpm) / 140.13 CFM (1,500rpm)
Effective Airflow Range 0.3m ~ 3.5m
Static Pressure 0.24mmH2O (400rpm) ~ 3.17mmH2O (1,500rpm)
Air speed at fan edge 0.7m/s ~ 3.7m/s
Noise Level 18 dBA (400rpm) ~ 37dBA (1,500rpm)
So I guess my 3 fans probably move around 150 CFM combined around my typical RPM, at around 20db
Currently have a single Scythe S-flex 1200rpm fan in the top exhaust, which has no hope of turning the case from fully positive pressure to neutral
![Smile :)](./images/smilies/icon_smile.gif)
Will be swapping in a Noctua S12b, that I bought many years ago, but was too lazy to install....