Short answer: the be quiet! Pure Power 13 M is my quiet pick on a budget, and the be quiet! Dark Power 14 is the one for a near-silent high-end build. If you game for long sessions, choose a unit with headroom so the fan rarely needs to spin up.
How noise is measured
Noise is measured in dBA, which weights sound to match how loud it seems to people. Every 10 dBA step sounds roughly twice as loud. A quiet room sits around 25 to 30 dBA, so a power supply below that is hard to hear inside a closed case.
Cybenetics gives power supplies a noise grade called LAMBDA, based on their average noise across its tests:
| LAMBDA grade | Average noise |
|---|---|
| A++ | Below 15 dBA |
| A+ | 15 to 20 dBA |
| A | 20 to 25 dBA |
| A- | 25 to 30 dBA |
| Standard++ | 30 to 35 dBA |
| Standard+ | 35 to 40 dBA |
| Standard | 40 to 45 dBA |
Check the LAMBDA grade on a product page or review where you can. It tells you more than a "silent" claim on the box.
The quietest picks, by the lab results
- Quiet pick, Tier B · Tier Bbe quiet! Pure Power 13 M80 Plus Gold · Fully modular · ATX · 750/850/1000/1200WHWBusters measured average noise around 10.5 dBA. Club386 found the fan stays off until about 50% load.Check 850W price
- Near-silent, Tier A · Tier Abe quiet! Dark Power 1480 Plus Titanium · Fully modular · ATX · 850/1000/1200WHWBusters called its noise dead-low. PC Games Hardware gave the 1200W model its Silent award.Check 850W price
- Quiet and tidy · Tier ACorsair RMx Shift80 Plus Gold · Fully modular · ATX · 750/850/1000WHWBusters called it one of the quietest 850W units it has tested.Check 850W price
- Quiet at everyday loads · Tier ACorsair RMx (2024)80 Plus Gold · Fully modular · ATX · 750/850/1000WQuiet in normal use, with a knob to set the fan’s minimum speed. KitGuru found it audible at full load.Check 850W price
- Quiet at high power · Tier ACorsair HXi (2025)80 Plus Platinum · Fully modular · ATX · 1200/1500WIn Tom’s Hardware’s cooler test the fan stayed off until about 600W.Check 1200W price
Quiet picks compared
| Unit | Fan stays off until | Worth knowing |
|---|---|---|
| be quiet! Pure Power 13 M | About 50% load (Club386) | No fan failure protection |
| be quiet! Dark Power 14 | About 70% load on the 1200W model (PC Games Hardware) | No fan failure protection |
| Corsair HXi (2025) | About 600W in Tom’s Hardware’s test | Expensive, and 200mm long |
| Corsair RMx Shift | Side sockets don’t suit every case |
What makes a power supply quiet
- Semi-passive fan mode. The fan stays off at light loads and only spins up when needed. Most of my quiet picks do this.
- Headroom. A unit running at half its rating runs cooler, so the fan spins slower. See the wattage guide.
- Efficiency. Less wasted power means less heat to remove. See efficiency ratings explained.
- Fan size and bearing. Bigger fans move the same air at lower speeds. Fluid dynamic bearing fans also tend to stay quieter as they age.
How to keep any power supply quieter
- Mount it fan down if your case has a vent and dust filter underneath, so it breathes cool air from outside the case.
- Keep the filter clean. A clogged filter makes the fan work harder.
- Size up a step. Moving from 750W to 850W keeps the fan in its quiet range for longer while gaming.
- Check where the noise is coming from. High-pitched whine at high frame rates is often the graphics card, not the power supply. A frame rate cap usually helps.
A trade-off to know about
Some of the quietest units skip fan failure protection. Lab reviewers noted it's missing on both be quiet! picks. It means the unit won't shut down by itself if the fan stops. In practice, a fan failure in a good unit is rare, but if that bothers you, the Corsair RMx (2024) and Corsair HXi (2025) both include it.
Questions
Why is my power supply fan not spinning?
Many quiet units turn the fan off at light loads on purpose. It should start under heavier load, such as gaming.
What is a good noise rating for a power supply?
A Cybenetics LAMBDA grade of A- or better means average noise below 30 dBA, which is quiet in most rooms.
Is a bigger power supply quieter?
Often, yes. At the same load it runs further from its limit, so the fan spins slower or stays off.
Are SFX power supplies quiet?
At light loads many are. Under heavy load their small fans spin faster, so they are usually louder than ATX units.
Why does my PC whine during games?
It’s often graphics card coil whine. It is common, usually harmless, and a frame rate cap often reduces it.
Sources
- Cybenetics: LAMBDA noise ratings for power supplies
- HWBusters: be quiet! Pure Power 13 M 850W review
- Club386: be quiet! Pure Power 13 M 850W review
- HWBusters: be quiet! Dark Power 14 850W review
- PC Games Hardware: be quiet! Dark Power 14 test (German)
- HWBusters: Corsair RM850x Shift ATX 3.1 review
- KitGuru: Corsair RM850x ATX 3.1 review
- Tom's Hardware: Corsair HX1200i ATX 3.1 review
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