Reviewed: be quiet!’s new Shadow Rock Slim 2 CPU Cooler

Parts used for this review

Coolerbe quiet! SHADOW ROCK SLIM 2 (sent by be quiet!)
Comparison CoolerDeepCool AS500 Plus Air Cooler (sent by DeepCool)
Comparison CoolerNoctua NH-D15 (sent by Noctua)
Comparison CoolerEnermax LIQMAX III 240mm ARGB (sent by Enermax)
Additional Fan Scythe Kaze Flex 140mm 1200RPM (sent by Scythe)
Thermal PasteNoctua NT-H1 (purchased from Amazon)
CPUIntel i9 10900K @ 4.8ghz (sent by Intel)
MotherboardASRock b560 Steel Legend (sent by ASRock)
Computer CaseBeQuiet! Silent Base 802 Window (sent by be quiet!)

Today we’ll be looking at be quiet!’s new SHADOW ROCK SLIM 2, which just launched. be quiet! offered us the opportunity to test it prior to release, and we’ve had a few weeks to become familiar with it. While recently I have been testing higher end coolers, this cooler is priced at the lower end of the mid-range segment at only $45.90 USD (€45.90 / £43.99). While it’s only officially rated for 160w, I found it to be capable of handling more than that – but before we dive into benchmarks let’s take a look at the cooler and it’s packaging.

The SHADOW ROCK SLIM 2 comes in a medium sized box, with cardboard and thin foam inserts for protection.

Included with the package are the user manual, thermal paste, mounting parts for AMD & Intel based systems, fan brackets for 2x fans, 1x 135mm fan, the heatsink, and the securing rod for the heatsink.

Cooler Specifications

Coolerbe quiet! SHADOW ROCK SLIM 2
Heatsink Dimensions52x130x161mm
Net Weight685g
Fin MaterialAluminum
Base materialCopper
Fan Compatibility135×135
Rated TDP (Official)160W
Rated TDP (Our estimate)200w, if not overclocking
Warranty3 years
Price (MSRP)$45.90

Fan Specifications

There’s more to a cooler than just it’s heat sink. The fans included have a huge impact on cooling performance and noise levels.

Fan135mm be quiet!
Max Fan Speed1400RPM
Air Flowunknown
Static Pressureunknown
Rated Overall Noise23.7 dB(A) at 100% fan speed
Bearing TypeRifle bearing
Rated Voltage12 V


The installation of be quiet’s cooler wasn’t difficult, but it felt more complicated than it needed to be. The clips for the fans were flimsy and it was easy to accidentally install the middle support bar upside down – which prevents the cooler from maintaining proper tension.

Testing Methodology

I use Noctua’s NT-H1 thermal paste for all cooler testing, to eliminate any variances that could be caused by using different pastes. For the most demanding loads, such as Prime95, I also tested the SHADOW ROCK SLIM 2 with an added Scythe Kaze Flex 2 140mm 1200 RPM fan to see how much cooler it would perform.

For Cinebench and AIDA64, I ran each test for 10 minutes – but removed the first 2 minutes of temperature data to account for the warm up period (testing for longer periods did not produce significant differences). For games, I used a scripted benchmark and averaged the results of 3x runs. I tested each cooler with no power limits, as they were each capable of handling the heat.

In the future, I will only perform TDP limited testing on coolers which thermally throttle in torture testing. While TDP limited testing is interesting, most DIY users with high end CPUs will be running without power limits. Because the SHADOW ROCK SLIM 2 was only rated for 160w by be quiet!, I didn’t expect it to pass my testing without power limits – but I was pleasantly surprised to find that it handled my i9 just fine outside of Prime95 Small FFTs.

No Power Limits Testing

In AIDA64 all of these coolers ran a little warm – and the SHADOW ROCK SLIM 2 ran at the limits of what I would consider acceptable at 91c (at 25c ambient). Adding Scythe’s Kaze Flex fan to the be quiet! cooler helped tremendously here, dropping temperatures an additional 7c – bringing it’s cooling performance in range of high end coolers twice its price.

Cinebench r23 also ran at the limits of what I would consider acceptable, but still passed with 91c (at 26c ambient). This is a budget cooler after all, and isn’t something you’ll be using to win overclocking contests. If you did want to give it a mild overclock using be quiet!’s new cooler, adding Scythe’s Kaze Flex 140mm fan to it reduced temperatures by an additional 6 degrees.

Prime95 Small FFTs was the only load where the SHADOW ROCK SLIM 2 couldn’t handle the heat well, but in this load it was consuming an average of 230w and while throttling due to hitting TJMax it still maintained 4.6ghz – and really that’s pretty good considering that it’s dealing with 70w more TDP than it’s designed to handle.

Even with an additional fan added the cooler still hit TJMax in Prime95 Small FFT testing, causing throttling. However it was 100mhz faster than testing in the default configuration and consumed 249w – 19w more than with just a single fan. The above only shows results for the be quiet! cooler in Prime95 because I have not tested it with other coolers yet, but I will update the results with additional coolers as I test them.

In gaming, all coolers did well – with Far Cry V having the worst results for the be quiet cooler with 64c (over 25c ambient)


I purchased a Decibel Meter to more accurately report acoustic information, but I found it difficult to take consistent measurements with it – so instead of using the Decibel Meter, I’ve taken audio recordings of the fans during stress tests and analyzed them with Orban Loudness Meter. Of all the coolers I have tested thus far since changing my testing methods, the SHADOW ROCK SLIM 2 has been the quietest by far.


At only $45 the new be quiet! SHADOW ROCK SLIM 2 isn’t an expensive cooler, but surprisingly was able to handle every load I threw at it with no power limits with the exception of Prime95 Small FFTs – and in that scenario it was able to handle 230w, a whopping 70w more than it’s actually rated for. It does this while providing the quietest experience of any CPU cooler I have tested thus far.

While this isn’t a cooler you’d want to use for overclocking an i9-11900k, and would be best paired with something easier to tame like an i5-11400, it can definitely handle any consumer CPU on the market. It’s only officially rated for 160w TDP, but I find the SHADOW ROCK SLIM 2 capable of handling up to 200w comfortably – a nice change from coolers which overstate their TDP ratings. If you did want to add a little cooling power to it, adding a 2nd fan brings temperatures down by an additional 7c.

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