be quiet! Pure Rock Slim 2 CPU Air Cooler Review

The Little Cooler That Could

Be quiet! has been around long enough, and been producing enough quality products, that most PC enthusiast know of their products. Their Dark Rock and Dark Rock Pro series of coolers have long been among the very best performers in their respective classes, and still lived up to the nom de guerre of the company. Unlike many other well regarded CPU cooler and fan manufacturers, be quiet! regularly release updated and improved versions of their products, showing that they don’t rest on their laurels.

In other reviews, I have stated that my personal air cooler of choice for high-end builds and silence is the Dark Rock Pro (I currently have two of the Dark Rock Pro 3 in use). I’ve never had the opportunity to try out any of their water coolers, power supplies, or cases, but I know that some of the other PC Perspective writers are impressed with those as well.

Given my fondness for be quiet! coolers, I was happy to see a package arrive unexpectedly from them. (Review samples can happen without warning, or if I forget to tell you. – Ed.) There was something a little different with this though, the package was simply too small to be a CPU cooler (or so I thought), but when I opened the package I was greeted by a familiar black, silver, and orange be quiet! box which contained their most recent CPU cooler, the Pure Rock Slim 2.

Pure Rock Slim 2 Cooler Design and Installation

This is an updated version of the Pure Rock Slim, which appears identical, but be quiet! has stated that the new version is capable of dissipating 130w of heat, over the 120w of its predecessor.

If my mention of the size of the shipping box did not make it clear, the Pure Rock Slim 2 is small. This tower cooler is only 135mm tall, and uses a 92mm Pure Wings 2 fan. The cooler uses three 6mm copper heat pipes which directly contact the CPU heat spreader. The small size of the cooler, and the use of only 3 heat pipes, gave me some initial misgivings of what this cooler would be capable of. As you will see in the testing, I was wrong.

While this is not the cooler for you if you are looking to air cool your Ryzen 5950x (or even 5800x), this is probably the perfect cooler for a lot of people out there, especially given it’s bargain basement MSRP of $25.90 US.

Just on initial inspection, this was exactly the quality of cooler that I’ve come to expect from the be quiet! brand. The Pure Rock Slim 2 is well made, and has a quality feel to the cooler and the fan, and is attractively designed. It comes with the AMD mounting adapter pre-attached. The AMD mount uses two tension clips which hook to the stock plastic bracket that’s been on AMD socket motherboards since AM2 was released in 2006.

I have seen many coolers that utilized this style of attachment on AMD motherboards over the years, with mixed results. Some held good tension and pressure, but some were so bad that you could actually slide the cooler around on top of the CPU. Fortunately, that was not the issue here as the Pure Rock Slim 2 was extremely easy to mount onto my AMD test bench, and once there, it was secure and had very good mounting pressure.

Unfortunately, I was not as pleased with the Intel mount. Be quiet! apparently was going for retro mounting with the Pure Rock Slim 2 and utilized push clips for the include Intel brackets. While once the cooler was mounted, it did seem to have good mounting pressure, it was a complete pain in the Jordan to get it mounted. If anyone out there has a time-traveling DeLorian, one of the best things they could do would be to go back and backhand slap the engineer who decided that push clips were the way CPU coolers should mount ( I know, that’s not how time travel works, thank you Dr. Banner).

The Pure Rock Slim 2 comes with thermal paste pre-applied to the base. I did have one small issue with this as the plastic packaging for the cooler had contacted the thermal paste and lightly smudged it, though I do not believe this was bad enough that it would cause problems to the end user.

The direct contact base plate on the Pure Rock Slim 2 was another pleasant surprise, and another example of the exceptional eye for detail that always seems apparent in be quiet! products I’ve used. As I always use IC Diamond graphite thermal sheets for my testing, I cleaned the pre-applied thermal paste and examined the base plate. This was, by far, the most consistent, and smoothest machining I have ever seen on a direct contact cold plate. There were no visible gaps between the copper and the aluminum. It was amazing and appeared at smooth and flat as any standard base plate I have ever seen.

Pure Rock Slim 2 Performance

Ok, so the Pure Rock Slim 2 looks nice, is well made, and it is small. How does it actually perform in the task it is designed for, cooling a CPU? Let’s take a look.

For testing, I ran the OCCT small data set stress test for 20 minutes in an InWin Alice test bed. All tests conducted at a controlled ambient temperature of 23 C.

Test System Specs:

• AMD Ryzen 5 3600x (4.3 Ghz All Core, 1.4 volts)
• MSI B350M Mortar Arctic Motherboard
• 16 GB (2×8) Corsair Vengeance LPX DDR4 3200 Memory
• EVGA GTX 980 SSC
• Western Digital Black 256 GB NVMe SSD
• IC Diamond Graphite Thermal Pad (used on all coolers for consistency in testing)

The Pure Rock Slim 2 was actually able to keep the overclocked Ryzen 3600x on my test bed from throttling. It performed almost equal to the AMD Wraith Prism cooler (while being immensely quieter), and outperformed the Wraith Spire cooler (which was unable to complete the test). The Pure Rock Slim 2 came within two degrees of matching its larger and more expensive brother, the be quiet! Shadow Rock 3. The Pure Rock Slim 2 fan was ever so slightly louder (and a little higher pitched), the fan on the Shadow Rock 3, due to higher RPM and smaller size.

This was only the case at full fan speed on an overclocked CPU under loads than most people will put their system under. At normal voltages and clock speeds on a 65w Ryzen 1600 processor, I had a peak temperature of 63 degrees (40 over ambient) in the same OCCT stress test while using the Pure Rock Slim 2. At the same time, I was unable to hear the 92mm Pure Wings fan over the Noiseblocker case fans. At any RPM under around 1200, most people would never hear this fan, especially not over most other case fans, GPU fans, or even over normal ambient noise levels.

Honestly, when I took this tiny cooler out of the packaging, I did not have much hope for it. I thought it would certainly not complete my test run without causing the CPU to throttle. Be quiet! proved me wrong. I came away from my testing impressed with the performance of this small and inexpensive CPU cooler.

Conclusion

In the end, the verdict on the Pure Rock Slim 2 comes down to what the end user is looking for a cooler to do. As I mentioned earlier, if you are overclocking (or even running a high TDP CPU at stock clocks) then you should definitely look elsewhere. If you’ve picked up any generation of Ryzen with a TDP of 95 watts or less, and you either don’t have a stock cooler, or just want less noise, then for $26 you simply can’t beat this. While it is true that something like a Cooler Master Hyper 212 will slightly outperform this, again the Pure Rock Slim 2 is only $25.90.

If you’ve got a PC being used for a purpose that silence is important to you (such as an HTPC), and you can fit a cooler that’s 135mm tall, the Pure Rock Slim 2 would be an excellent choice. In such a circumstance, it is unlikely you would ever load the CPU enough for the 92mm Pure Wings 2 fan to reach speeds that would make it audible.

When you consider the price, the performance, and the form factor of the Pure Rock Slim 2, this is a CPU cooler that is almost in a class by itself. I would recommend this cooler to anyone who needs something inexpensive, small and quiet. My only complaint with the Pure Rock Slim 2 is about the choice to use push pin mounting clips on the Intel adapters, but I don’t know if be quiet! could have hit such a low price point if they had gone with another Intel mounting system. I am happy to give the be quiet! Pure Rock Slim 2 the PC Perspective Gold award.