When it comes to a mid-tier CPU cooler, be quiet! has a stellar offering available in the Dark Rock Slim. Not only does it perform well, it does so while being whisper quiet. Maxing out at just 38 dBA in our tests with the fan at 100%, it manages to keep the Intel i7-8700K in our test bench from thermal throttling in the OC FPU test. However, Noctua's NH-U12S and Thermalright's TRUE Spirit 140 Direct give it some serious competition. The NH-U12S, while much older, performs quite well and can generally be found at similar pricing, but it's a tad louder. Meanwhile, the TRUE Spirit 140 Direct, while offering similar performance for a bit less, is also quite a bit larger and gets pretty close to the system memory as well. Even so, for the performance on offer here, be quiet! hits a nice compromise between features, price, performance, and looks.

The only issue here, and it won't be for many, is the lack of RGB LEDs. I am glad to see a performance and quality-focused offering rather than another "hey, look at me, I'm trendy right now" design. Even so, in the age of RGB, some will likely give the Dark Rock Slim a pass since it is not flashy enough. With that said, other options that perform better at a similar price without sacrificing low noise output are available, like the Scythe Ninja 5. However, you give up memory clearance to get said performance improvement at a similar cost.

Overall, if you take an objective look at what is on offer here, I really can't find any reason not to recommend be quiet!'s latest offering. I certainly wouldn't recommend the cooler for hardcore overclockers or users wanting to push things to the limit, but then again, that is what the Dark Rock Pro 4 is meant for if you are sticking with air cooling. Users looking for a small overclock on all cores without listening to the stock heatsink and fan ramp up like a leaf blower will likely want to add the Dark Rock Slim to their short list of available options.

My only gripe here, and it's not really a negative, is that judging from the cooler's noise profile, it is obvious be quiet! could have pushed the fan RPM a bit higher to gain a bit more performance. There is room here for temperatures to drop another degree or two while still staying at or below 40 dBA when the fan ramps up to 100% PWM. This would deliver performance closer to the venerable NH-U12S while still being quieter. Even so, considering the company name, I would likely expect them to focus more on low noise and less on pure performance.