The 120mm fan figures are grouped by the top speed each one is printed at, by frame depth, and by whether an adaptor or switch capped the speed, so a fan is ranked only against fans stated the same way.
Every maker here prints dB(A) at a fan's top speed. Noctua calls it "Max. acoustical noise", be quiet! labels the row "at 100% PWM / 12V", Thermalright adds "(MAX)", and Lian Li writes "dB(A) Max". Scythe and Corsair print a range from the slowest to the fastest setting, and we take the upper end, which belongs to the top speed.
Within that basis we draw five bands:
- Noctua's slow editions: 700 to 900 RPM
- Quiet-first fans: 1100 to 1300 RPM
- Mainstream fans: 1500 to 2200 RPM, 25 to 26 mm deep
- Thick frames: 28 to 30 mm deep
- Slim frames: 15 mm deep
A figure taken through a Low-Noise Adaptor or a profile switch is a lower speed by design, so those sit in their own section and never join a band.
What is the quietest 120mm fan below 1300 RPM?
Noctua's NF-A12x25 LS-PWM lists the lowest figure among 120mm fans topping out between 1100 and 1300 RPM: 12.1 dB(A) at 1200 RPM. Slower Noctua editions print lower numbers, at 700 to 900 RPM.
Five fans fall in the 1100 to 1300 RPM band:
- Noctua NF-A12x25 LS-PWM: 12.1 dB(A) at 1200 RPM, 55.7 m³/h
- Shadow Wings 2 120mm PWM: 15.9 dB(A) at 1100 rpm, 38.5 CFM (be quiet!)
- Noctua NF-S12A PWM: 17.8 dB(A) at 1200 RPM, 107.5 m³/h
- Scythe Wonder Snail 120 PWM 1200rpm: 18.6 dBA at 1200 rpm, 37.73 CFM
- Noctua NF-P12 redux-1300 PWM: 19.8 dB(A) at 1300 RPM, 92.3 m³/h
The LS-PWM leads by 3.8 dB, which is a clear gap even with no shared test rig. The NF-S12A is the interesting third: it moves almost twice the LS-PWM's air at the same 1200 RPM for 5.7 dB more.
Noctua's 700 to 900 RPM editions
Only Noctua sells 120mm fans this slow with a figure attached, so this group is one maker's ladder. The NF-S12B redux-700 prints 6.8 dB(A) at 700 RPM, the NF-S12A ULN 8.6 at 800, and the NF-P12 redux-900 12.6 at 900.
These are the smallest numbers on the page, and they buy the least: 56.9, 74.3 and 63.4 m³/h, with just 0.44 mmH2O of pressure on the redux-700.
Which 120mm fans are quietest between 1500 and 2200 RPM?
The be quiet! Silent Wings 4 120mm PWM lists the lowest figure between 1500 and 2200 RPM, 18.9 dB(A) at 1600 rpm. The next lowest are be quiet!'s Light Wings at 20.6 and two Noctua fans at 22.4 and 22.5.
Ten fans with 25 to 26 mm frames top out in this band, each printed at its own top speed:
- Silent Wings 4 120mm PWM: 18.9 dB(A) at 1600 rpm (be quiet!)
- Light Wings 120mm PWM: 20.6 dB(A) at 1700 rpm (be quiet!)
- Noctua NF-F12 PWM: 22.4 dB(A) at 1500 RPM
- Noctua NF-A12x25 G2 PWM: 22.5 dB(A) at 1800 RPM
- Scythe Wonder Snail 120 PWM 1800rpm: 22.9 dBA at 1800 rpm
- Noctua NF-P12 redux-1700 PWM: 25.1 dB(A) at 1700 RPM
- Pure Wings 3 120mm PWM: 25.5 dB(A) at 1600 rpm (be quiet!)
- Thermalright TL-C12C: 25.6 dBA (MAX) at 1550 RPM
- Thermalright TL-B12: 28.1 dBA (MAX) at 2150 RPM
- Corsair RS120: 36 dBA at 2100 RPM
Speed explains part of the spread, but not all of it. The Silent Wings 4 and Pure Wings 3 share a maker, a test setup and a 1600 rpm top speed, yet be quiet! prints 18.9 for one and 25.5 for the other.
That 6.6 dB gap within one brand is the clearest evidence in the band that blade, frame and bearing design matter, not RPM alone.
The middle of the list is crowded. The NF-F12, G2 and Wonder Snail 1800 sit within 0.5 dB of one another, a gap that no maker's unstated test conditions can separate.
Are thick 120mm fans louder?
Yes, thick 120mm fans list higher figures than the quietest standard fans, because makers run them faster for pressure. At a shared 2000 RPM, Lian Li's 28 mm AL120 V2 lists the lowest, 28.7 dB(A) Max.
Three 28 to 30 mm fans share a 2000 RPM ceiling, which makes this the tidiest comparison on the page:
- Lian Li UNI FAN AL120 V2, 28 mm: 28.7 dB(A) Max, 77.3 CFM, 2.97 mmH2O
- Lian Li UNI FAN SL120 V2, 28 mm: 29.2 dB(A) Max, 64.5 CFM, 2.59 mmH2O
- Corsair RS120 MAX, 30 mm: 29.5 dBA, 72 CFM, 4.2 mm-H2O
The spread is 0.8 dB. Corsair's fan gives the most pressure of the three, the AL120 V2 the most air.
Phanteks' 30 mm T30-120 runs to 3000 RPM and prints 39.7 dBA there, with 7.37 mm H2O, more pressure than any fan on this page. Lian Li's own chart puts the 28 mm UNI FAN TL 120 at 33 dB(A) and the P28 at 32.1, both at 2600 RPM.
What is the quietest 120mm radiator fan?
Noctua's NF-A12x25 G2 lists the lowest figure among 25 mm fans rated above 3 mm of water at full speed: 22.5 dB(A) at 1800 RPM with 3.14 mmH20. The other two are louder and spin faster.
Static pressure is the number that decides how well a fan pushes through radiator fins. Here is each 25 mm fan rated above 2.5 mm, with its noise at the same top speed:
- Corsair RS120: 4.15 mm-H2O, 36 dBA at 2100 RPM
- Silent Wings 4 high-speed: 3.96 mm H2O, 31.2 dB(A) at 2500 rpm (be quiet!)
- Noctua NF-A12x25 G2: 3.14 mmH20, 22.5 dB(A) at 1800 RPM
- Thermalright TL-B12: 2.87 mm H2O, 28.1 dBA at 2150 RPM
- Noctua NF-P12 redux-1700: 2.83 mmH2O, 25.1 dB(A) at 1700 RPM
- Noctua NF-F12: 2.61 mmH2O, 22.4 dB(A) at 1500 RPM
Thick frames add more pressure: 4.2 mm-H2O on Corsair's RS120 MAX at 29.5 dBA and 7.37 mm H2O on the T30-120 at 39.7 dBA.
Scythe pitches the 1800 rpm Wonder Snail at radiators too, at 1.74 mmH2O. ARCTIC's P12 Max lists 4.35 mmH2O but rates loudness in sone, so it stays out of this list.
What the pressure numbers leave out
Each pressure figure is the fan's maximum against a closed outlet, measured by its maker on its own rig. None of the seven makers publishes noise for a fan bolted to a radiator core, where the fins change both the airflow and the sound.
Use the list to shortlist fans that can push through a core, then run them as slowly as your temperatures allow.
What is the quietest slim 120mm fan?
Noctua's NF-A12x15 PWM is the only 15 mm slim 120mm fan we found with a noise figure tied to a speed: 23.9 dB(A) at 1850 RPM, or 16.8 dB(A) at 1400 RPM through its adaptor.
With nothing comparable, it is a pick by default rather than by ranking. It gives up some pressure to the 25 mm Noctuas, 1.53 mmH2O against 2.61 on the NF-F12, but moves 94.2 m³/h from a frame 10 mm thinner.
Slim fans matter for low-profile CPU coolers and compact cases, where a 25 mm frame would hit a side panel or a memory module.
Does a low-noise adaptor make a fan quieter?
Yes, a low-noise adaptor makes a fan quieter by lowering its top speed, and Noctua prints the result: its NF-A12x25 G2 drops from 22.5 dB(A) at 1800 RPM to 18.1 at 1500 with the adaptor fitted.
Noctua is the only maker here that prints a second column for an adaptor. These are the 120mm adaptor figures on our list, each at its capped speed:
- NF-S12A ULN: 6.7 dB(A) at 600 RPM
- NF-A12x25 LS-PWM: 7.6 dB(A) at 900 RPM
- NF-S12A PWM: 10.7 dB(A) at 900 RPM
- NF-A12x15 PWM: 16.8 dB(A) at 1400 RPM
- NF-A12x25 G2: 18.1 dB(A) at 1500 RPM
- NF-F12 PWM: 18.6 dB(A) at 1200 RPM
Noctua's NF-S12A FLX shows the ladder in one box: 17.8 dB(A) at 1200 RPM bare, 10.7 at 900 with the Low-Noise Adaptor and 7.4 at 700 with the Ultra-Low-Noise one.
A PWM curve in the motherboard does the same job without a cable, and keeps the top speed for when the fan needs it.
Phanteks takes a third route on the T30-120, a switch on the frame. Its Performance profile caps the fan at 2000 RPM and 27.3 dBA, and Hybrid at 1200 RPM and 9.8. We keep those apart from Noctua's adaptor columns, since the mechanism and the maker differ.
Is Noctua quieter than be quiet!?
No, Noctua is not consistently quieter than be quiet! on the makers' own sheets. be quiet!'s Silent Wings 4 beats Noctua's mainstream fans in its speed band, while Noctua's LS-PWM beats be quiet!'s Shadow Wings 2 below 1300 RPM.
The closest matches by speed tell the story. At 1600 rpm the Silent Wings 4 lists 18.9 dB(A); Noctua's nearest, the NF-F12 at 1500 RPM, lists 22.4. Below 1300 RPM, Noctua's LS-PWM lists 12.1 at 1200 RPM against 15.9 for the Shadow Wings 2 at 1100.
Neither maker states a microphone distance, so a brand rule cannot be read from these sheets. Noctua offers the longer warranty, six years against five on the Silent Wings 4.
Which 120mm fans could not be ranked?
Four 120mm fans could not be ranked: the Phanteks M25 G2 120, Fractal Design Momentum 12, Corsair AF120 ELITE and ARCTIC P12 Max, because each figure lacks a speed, conflicts with itself or uses sone.
Phanteks prints 35.13 dBA beside a speed range of 350 to 2000 RPM, and Fractal prints 28.03 dBA beside 350 to 2200 RPM. Neither says which speed the figure belongs to, so neither can join a band.
Corsair's AF120 ELITE carries two numbers on one page: a spec table range of 5 to 28.9 dBA and marketing copy claiming it "spins as quietly as 31.5 dba". The claim reads as a floor and contradicts the table, so we quote both and rank neither.
ARCTIC rates the P12 Max at 0.6 sone with no speed. Sone measures perceived loudness on a different scale, and ARCTIC gives nothing that would let it sit beside dB(A).
