In the past, my testing of coolers had focused on Intel CPUs because they were the most challenging to cool and also consumed the most power. Some of you may remember that when Alder Lake was released, I remarked that the thermal difficulty of cooling the 12900K was more difficult compared to prior generation products, and in turn most coolers were unable to keep the CPU under TJMax under the most intensive workloads.
Raptor Lake was even harder to cool, and as a result I had to change my testing methods because literally no cooler (at least, none that I had tested) was able to keep the CPU under TJmax under the most intensive of workloads.
Well, higher temperatures are no longer just an Intel thing – modern AMD CPUs are also designed to run at their peak temperatures during the most intensive workloads (they do, however, consume less power than their Intel counterparts).
As the manufacturing processes of CPUs continue to shrink their thermal density will also continue to rise – meaning that the difficulty of cooling processors in heavy workloads will only become harder in the future.
I have been interested to see how different levels of cooling performance effect both AMD and Intel platforms for some time. Thanks to our partner ASRock this is now possible – they sent a sample of their B650E Taichi for testing purposes. I will be taking a closer look at this motherboard in the future – but in the meantime check out reviews of this pristine motherboard on Funkykit & Tom’s Hardware.
Introducing BeQuiet’s Pure Rock LP, a compact SFF cooler
German company Be Quiet, founded in 2001, is well known amongst enthusiasts for their capable coolers with quiet performance. I’ve most recently tested their Pure Loop 2 FX, which I found capable of handling up to 285W loads with Intel’s i9-13900K. They’re also known for their lineup of power supplies and cases – their Silent Base 802 is one of my favorite cases on the market.
Packaging and Included Contents
Be Quiet’s Pure Rock LP arrives in a small box, approximately 5″x5″x3.5″ in size.
The Celsius+ S28 comes with pre-applied cooling paste, a 280mm radiator and RGB CPU block, 2x 140mm fans, a user guide, and mounting for modern AMD & Intel platforms. Included in the box are the SFF heatsink & fan, the instruction manual, and mounting adapters for both AMD & Intel platforms.
Installation of the Pure Rock LP
The installation of the Pure Rock LP is fairly simple, the process is virtually the same on both AMD and Intel platforms. With AM4 and AM5, you’ll want to start by removing the default retention socket.
Next, you’ll need to attach the mounting brackets to the heatsink. If you’re using Intel, you’ll need to insure the studs are aligned in the correct position.
Now comes the tricky part – to secure the cooler, you’ll need to press it against the CPU and thread the screws through the holes on the back of the motherboard (through the backplate on AMD systems)
The Pure Rock LP has the smallest profile of any Be Quiet! cooler. At only 45mm height, it’s compact enough to fit into even the most space constrained Mini-ITX builds.
Full Copper CPU plate with pre-applied thermal paste
Solid Cooling Efficiency
The Pure Rock LP has strong cooling capacity for it’s small size, Be Quiet claims 100W of cooling performance with this 3 heatpipe design.
92mm PWM Fan
There’s more to a cooler than just it’s heat sink, the fans paired with a cooler have a huge impact both total cooling potential and noise levels – included with the Pure Rock is a 92mm low profile fan designed for quiet cooling.
As I have limited time to test coolers on the AM5 platform, today’s article will have limited comparison results for Ryzen 7 7700X – this is more of an introduction to how various types of cooling will impact potential cooling performance.
At the default “TDP” of 105W, the most intensive loads can be difficult to cool and often result in the CPU running at TJMax. As such, we’ll be looking at 3 Metrics in this situation: Noise levels, watts cooled, and benchmark scores.
Some of y’all might notice that the graph starts at 36 instead of zero – this is because my sound meter cannot measure noise levels lower than 36 dBA, effectively making it the noise floor for our testing purposes.
With total system noise levels of 41.4 dBA, the Pure Rock LP runs fairly quiet. More acoustic comparison results is available further down in this article with the Intel i9-13900K testing results.
If you’re wondering why the chart below starts at 36, it’s because that is the reading my noise meter records when my computer is turned off. This makes it the floor for my acoustic results. However, one should keep in mind that dBA results are logarithmic, meaning that differences in loudness will actually be more significant than what my dBA charts might seem to suggest.
To better make it easier to visualize the differences in dBA levels, BeQuiet has an informative video illustrating how much louder things really are as they increase in dBA.
In this situation where the CPU hits TJmax, another metric which is useful to compare cooling performance is the total watts cooled by the cooler.
Looking at the total watts cooled in this scenario, the Pure Rock LP is only able to cool 66W when paired with Ryzen 7700X. This isn’t necessarily a bad thing – after all, this is the smallest cooler I’ve ever tested.
How does the lower cooling capability translate into impacted performance? Not quite as significantly as you might think. While the Pure Rock LP is only capable of handling half the total power consumption of Iceberg Thermal’s G4 Silent single tower cooler, it provides 78.6% of the of the benchmark performance.
Put another way: While the G4 Silent has twice the cooling capacity of BeQuiet’s SFF cooler, performance only increased by 23%.
Unfortunately, as the Pure Rock LP was only able to cool 66W in our testing in our AMD system, that means this is where our comparison data for the Ryzen 7700X ends – the lowest comparison data I have for the other coolers is for 75W loads. Let’s take a look at how the Pure Rock LP performs with Intel’s Raptor Lake now.
Intel i9-13900K Thermal & Acoustic Performance
Power Limits Removed
The first metric I look at in heavy loads is noise. Total cooling capacity is nice, but noise levels are just as important. Nobody wants a jet engine in their computer, so how loud the cooler gets in these worst case scenarios is something you should consider when looking at coolers to purchase.
Looking at these results, we can see that the Pure Rock LP is a very quiet cooler.
You might wonder why these results show louder numbers than the Ryzen setup. The main reason is because of where I measure the noise levels. Originally I had thought it best to record noise levels with the soundmeter placed directly behind the computer. With my Ryzen 7700X system I am recording the measurements from the side of the computer as I feel this represents the true noise level more accurately. I would change how I measure the noise levels for Intel systems as well, but that would require going back and retesting all previously tested coolers – which I just don’t have the time to do.
In terms of total cooling capacity, the Pure Rock LP achieves approximately half of the cooling performance of a 360mm when paired with Intel’s i9-13900K – not bad for a tiny SFF cooler!
When limiting Intel’s i9-13900K to 125W, the CPU is extremely easy to cool – I wouldn’t be surprised if one of Intel’s old stock coolers could handle it without any problems. While I will show thermal performance results by measuring the delta over ambient temperature, I consider noise levels more important than thermal performance at this lower power limit.
While BeQuiet’s Pure Rock LP isn’t noisy in any sense of the word, it is the loudest cooler in the results shown here. However, given the more capable heatsinks and radiators of the larger coolers it’s tested against – I wouldn’t consider this to be a bad thing at all.
Thermal results follow the same pattern. While it is technically the warmest result shown, it’s nothing to worry about given that this is a tiny SFF cooler that is literally 1/10 of the size of some of the coolers it was tested against – and the CPU temperatures are well below TJMax.
I’ll be testing many more SFF coolers in the upcoming weeks, so stay tuned!
Handling 66W loads with Ryzen 7700X and 156W with Intel’s i9-13900K, BeQuiet’s Pure Rock LP offers a compact size that will fit even the tiniest and most cramped of cases while still offering decent cooling performance and low noise levels.
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