The Dark Rock series from be quiet! had to this point been on the larger side of CPU air cooler designs, but not everyone wants (or can even use) a large heatsink. And while be quiet! already has a lower-profile version in the Dark Rock TF, with the Dark Rock Slim the German company adds a slim, single-tower design to the family.

First revealed at CES 2019, the be quiet! Dark Rock Slim was officially launched in May, offering a premium take on the narrow single tower design of coolers like the ubiquitous Cooler Master Hyper 212 EVO, and boasting a cooling potential of up to 180W.

So how does the Dark Rock Slim perform? And how does that Hyper 212 EVO fit into all of this? Let’s get started!



“The Dark Rock Slim offers an exceptionally high cooling performance of 180W TDP and virtually inaudible operation. Perfect for high-end builds with limited space.”

The Dark Rock Slim arrives in the customarily well-protected packaging of a be quiet! product, and inside the box the heatsink and fan are encased separately in foam, with a box of installation hardware for both Intel and AMD systems.

We’ll look first at the heatsink, which measures 47.4 mm thick, 127 mm wide, and 159.4 mm tall. It features four 6mm copper heat pipes, a CNC-machined CPU contact surface, and what be quiet! describes as “airflow-optimized, wave-contoured cooling fins with small dots on their surfaces increase the air circulation”. The heatsink also features a black coating with ceramic particles to aid in heat transfer.

The included fan is the 120mm PWM version of the Silent Wings 3, a 7-blade airflow-optimized option that can spin at up to 1500 RPM, and offers a fluid-dynamic bearing, 6-pole fan motor, and funnel-shaped air inlets for high air pressure.

Installation is what we’ve come to expect from recent premium cooler designs: a backplate that is secured with standoffs around the CPU socket, followed by the installation of brackets to support the heatsink. Unlike Noctua designs, and similar to a Scythe cooler mount, the next step involves placing a bar across the base of the heatsink (as it is not attached), and then using the mounting screws to clamp this down against the bracket.

Once in place the fan attaches to the heatsink using metal clips on each side (a second pair is included if you’d like to add another fan), and as you can see this design poses zero interference issues as its footprint is primarily relegated to the space above the CPU socket.

With the Dark Rock slim installed on the cooler test platform let’s check out some performance numbers.

With the Core i7-7700K the be quiet! Dark Rock Slim was very impressive, lowering load temps by over 2.6 C vs the Hyper 212 EVO and 1 C over the improved Hyper 212 Black Edition.

From the results above it’s clear why the Hyper 212 has been such a popular option, with a 30+ degree drop in temps compared to the Intel stock cooler (which admittedly does not ship with the i7-7700K CPU – and for good reason!). The Black Edition from CM further improved temps, and now the Dark Rock Slim gives be quiet! a victory over these CM coolers with even better thermals.

As expected the idle noise from the Dark Rock Slim is all but nonexistent, with my SPL meter hovering near its minimum with average readings of 30.9 dBA. Inaudible on the test bench with any room noise whatsoever, it’s pretty safe to say you will not hear this cooler at idle inside a case.

Under full load things didn’t change significantly: just a 2 dBA increase was measured with the fan at its full 1500 RPM under a sustained CPU load, taking it up to 32.9 dBA. I could just hear it on the test bench standing only a couple of feet away, and ~33 dBA is still going to be inaudible in most cases.

With its stylish and functional black design, high quality materials and construction, solid thermals, and excellent noise performance, the be quiet! Dark Rock Slim is a great slim tower CPU cooler option. At its $59.90 list price it is quite a bit more expensive than the recently-reviewed Cooler Master Hyper 212 RGB Black Edition, but it offers better thermals and it is ultra quiet.

If you’re in the market for a capable air cooling option for your CPU but can’t use (or just don’t want) a large design that might hang over your memory, the Dark Rock Slim provides ample cooling without taking up much space around the CPU, and its mix of performance and nearly inaudible noise output will be hard to beat.

Editor-in-Chief at PC Perspective. Writer of computer stuff, vintage PC nerd, and full-time dad. Still in search of the perfect smartphone. In his nonexistent spare time Sebastian's hobbies include hi-fi audio, guitars, and road bikes. Currently investigating time travel.

Been using the CM 212’s in builds so long I can’t remember.. was I puttin them on P4’s or C2d’s first? Everything else looks like a knock off IMHO. $60 is more expensive than some water AIO’s. Looking at the review I’m left wondering the results would be if the BQ fan was installed on the 212? Good review!

Swapping fans would be an interesting test. How much are the improved thermals related to heatsink and how much is fan? The value proposition complicates things unless you already own one of the 212 coolers, of course… A 120mm PWM Silent Wings 3 fan is $21.90 US, with the 212 EVO and 212 Black Edition(non-RGB) ranging from about $30 – $37. At that point you’re looking at about $52+ and then the $59.90 price of the Dark Base Slim looks better.

This is where fan testing would make air cooler comparisons a little more granular. Time permitting we can look at it.

I would not go too deep in the weeds with fan testing. Most of that is not horribly useful or necessary until you start messing with radiators. I think a simple one pass fan swap with the BQ fan on the 212 would probably tell the tale.

As far as fan’s go I’ve been using nearly nothing but Nidec Servo Gentle Typhoon’s since I discovered them many years ago. But the price point on these is not tolerable for most people at $25ea depending on availability.

The 212’s go on sale for as little as $15.. I used stock up if I did have a couple sitting on the shelf.

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