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Black 120mm tower CPU cooler with four heat pipes and ARGB fan

be quiet!

be quiet! Pure Rock 3 LX BK040 120mm CPU cooler

SKU CH-GH8X-FY0KY MPN BK040

Compact 120 mm air cooler handles 190 W TDP with four 6 mm heat pipes and a 2000 RPM ARGB fan reaching 31.2 dBA

  • Fan size120 mm
  • Supported CPU socketsAMD Socket AM4 / AMD Socket AM5 / Intel LGA 1150 / Intel LGA
  • Bearing designRifle
  • TDP190 W
  • Rotational speed2,000 RPM max
  • Airflow rate61.8 CFM / 105.1 m3/h max
  • High 190 W TDP cooling for flagship CPUs
  • Light Wings LX 120 mm ARGB fan with funnel outlet for strong airflow and lighting
  • Four 6 mm heat pipes with HDT transfer heat efficiently
  • 2 dBA maximum noise at 2000 RPM for quiet operation
  • Compact 154 mm height fits most cases and clears tall RAM

Compact cooler for mainstream CPUs

The be quiet! Pure Rock 3 LX BK040 is a 120 mm air cooler rated for 190 W TDP. It fits Intel LGA 1150, 1151, 1155, 1200, 1700 and 1851 sockets plus AMD AM4 and AM5. Builders who need higher thermal headroom for extreme overclocking or passively cooled chassis should look elsewhere.

Thermals noise and power in daily use

Four 6 mm heat pipes with direct-touch copper bases move heat into an aluminum fin stack measuring 154 x 124 x 46 mm. The Light Wings LX 120 mm PWM fan spins up to 2000 RPM, delivering 61.8 CFM at 2.51 mm H2O pressure while peaking at 31.2 dBA. A 4-pin PWM connector lets the motherboard scale speed to actual load.

Behaviour under sustained load

The rifle-bearing fan maintains steady airflow through the funnel-shaped outlet during long gaming or rendering sessions. Heat-pipe capacity and fin density keep temperatures stable without abrupt ramp-ups. The 570 g assembly stays within standard keep-out zones, clearing tall RAM and VRM heatsinks on most ATX boards.

How it compares

Measured against everything we stock in CPU Coolers & Heatsink Fans, at today’s prices. Recalculated every night.

Price $31.99
Pricier than about 81% of the 1,559 comparable items (median $19.99).
Fan size 120 mm
Higher than about 80% of the 812 comparable items (median 80 mm).

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Specifications

Product
Brand namebe quiet!
Model namePure Rock 3 LX
Part numberBK040
Product colorBlack
Performance
Rotational speed2,000 RPM max
Airflow rate61.8 CFM / 105.1 m3/h max
Static pressure2.51 mm H2O
Processor
TDP190 W
Power
Power input connector4-pin PWM
Size & build
Fan size120 mm
Bearing designRifle
Cooler materialAluminum & Copper
Fan mountingVertical
Heatsink dimensions154 × 124 × 46 mm
Product weight570g
Shipping weight0.86 kg
Package size216 × 152 × 127 mm
Compatibility
Supported CPU socketsAMD Socket AM4 / AMD Socket AM5 / Intel LGA 1150 / Intel LGA 1151 / Intel LGA 1155 / Intel LGA 1200 / Intel LGA 1700 / Intel LGA 1851
CPU cooler height limit154 mm
Environment & compliance
Operating noise31.2 dBA max
More details
LED lightingAddressable RGB

Questions about this item

How do I install the Pure Rock 3 LX on an LGA 1700 socket, and which step do people often miss?

Use the preinstalled mounting bridge, align it with the LGA 1700 backplate holes, secure the spring-loaded screws diagonally, then connect the 4-pin PWM and ARGB cables — many forget the ARGB header.

What maintenance will the Rifle-bearing fan and ARGB lighting need over time?

Clean dust from the 120mm fan blades and 46mm-thick heatsink fins every 6–12 months; the Rifle bearing is sealed and the addressable RGB LEDs are not user-serviceable.

At what point does the 190 W TDP limit appear during a long, heavy workload?

When the CPU sustains more than 190 W the 4 × 6 mm heat pipes and 105.1 m³/h max airflow can no longer dissipate heat fast enough, so temperatures climb.

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