be quiet!
be quiet! Silent Wings Pro 4 140mm PWM High Speed 2400 RPM Premium Low Noise Cooling Fan | 4-Pin | BL099
Bottom line: The be quiet! Silent Wings Pro 4 140mm PWM High Speed 2400 RPM Premium ($29.90 on Amazon as of 2026-10-21 04:20 UTC): Three-position speed switch: medium, high, or ultra-high up to 2400 RPM; main trade-off: 2400 RPM ceiling is audible at max; the quiet claim applies to regular speed.
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*Price sourced from Amazon.com. Last updated 2026-10-21. Price and availability subject to change.
Pros & Cons
Pros
- ✓ Three-position speed switch: medium, high, or ultra-high up to 2400 RPM
- ✓ Funnel-shaped air outlet and small tip clearance for high static pressure
- ✓ Fluid-dynamic bearing plus 6-pole motor cuts vibration on long runs
- ✓ Standard 4-pin PWM header for full motherboard fan-curve control
Cons
- ✗ 2400 RPM ceiling is audible at max; the quiet claim applies to regular speed
- ✗ Speed switch is set on the fan itself, not adjustable from software
- ✗ Single-fan pack, so a 360mm radiator build needs three purchases
- ✗ Blade design targets radiators and heat sinks over open-air case airflow
Manufacturer description
The be quiet! Silent Wings Pro 4 140mm PWM fan is built for builders who want radiator-grade static pressure without the turbine whine that usually comes with it. Its optimized blade geometry, tight tip clearance, and funnel-shaped air outlet concentrate airflow into dense fin stacks, so it pulls its weight on a 360mm AIO or a tower cooler rather than just moving loose case air. A three-position speed switch lets you pick medium, high, or ultra-high-speed operation up to 2400 RPM, which means one fan covers both a quiet idle profile and a full-tilt thermal load without swapping hardware…
SpecPicks Verdict
SpecPicks scored be quiet! Silent Wings Pro 4 140mm PWM High Speed 2400 RPM Premium… using a rating × review-volume × price-fit model applied to published specs and reviews across the power supplies category. be quiet!'s power supplies lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.
Common buyer scenarios for power supplies of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the retailer's listing before purchase. Prices and stock are set by the retailer and may have moved since this page was last updated.
Frequently Asked Questions
How fast does the Silent Wings Pro 4 140mm spin?
Up to 2400 RPM in ultra-high-speed mode. A switch on the fan selects between medium-speed, high-speed, and ultra-high-speed maximums, and PWM control varies speed below whichever ceiling you choose.
Is this fan good for an AIO radiator or just case airflow?
It is designed for radiators and heat sinks. be quiet! cites optimized blade geometry, small tip clearance, and a funnel-shaped air outlet to generate extremely high air pressure through dense fin stacks.
Is it actually quiet at 2400 RPM?
be quiet! describes virtually inaudible operation at regular speed, not at the 2400 RPM maximum. Use the medium-speed switch position or a PWM curve for near-silent idle, and reserve ultra-high-speed for heavy thermal loads.
Will it work with my motherboard's fan curve?
Yes. It uses a standard 4-pin PWM connector, so any motherboard PWM header or fan controller can drive the curve. The onboard speed switch sets the upper limit that PWM scales against.
What bearing does it use and how long will it last?
It uses a fluid-dynamic bearing paired with a 6-pole motor for lower vibration and smoother operation. Check the product listing for current rated lifespan and warranty terms.
Key Features
- Optimized fan blades for the highest performance on radiators and heat sinks
- Speed switch allows changing maximum PWM speed between medium-speed, high-speed and ultra-high-speed (up to 2400 rpm)
- Small tip clearance and a fan frame with a funnel-shaped air outlet for extremely high air pressure
- Virtually inaudible operation at regular speed
- 6-pole fan motor and fluid-dynamic bearing for less vibration and very smooth operations
Full Specifications
| Brand | be quiet! |
|---|---|
| Model | BL099 |
| Voltage | 12 Volts |
| Wattage | 3.04 watts |
| Material | Copper |
| Set Name | PWM Pro Version |
| Unit Count | 1.0 Count |
| Noise Level | 36.8 Decibels |
| Part Number | BL099 |
| Compatibility | Switch |
| Material Type | Copper |
| Cooling Method | Fan |
| Number of Items | 1 |
| Vibration/Rumble | Yes |
| Air Flow Capacity | 97.4 Cubic Feet Per Minute |
| Compatible Devices | Radiator |
| Power Connector Type | 4-Pin |
| Warranty Description | 1 year |
| Maximum Rotational Speed | 2400 RPM |
| Item Dimensions L x W x H | 5.51"L x 0.98"W x 5.51"H |
Ready to buy?
be quiet! Silent Wings Pro 4 140mm PWM High Speed 2400 RPM Premium Low Noise Cooling Fan | 4-Pin | BL099 is listed on Amazon. Price, availability, shipping and returns are set by Amazon and its sellers — check the listing for current terms. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.
*Price sourced from Amazon.com. Last updated 2026-10-21. Price and availability subject to change.
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