Thermalright Assassin X 120 R SE Review: Quiet entry-level cooling for less than $20

CPU Thermal results without power limits

Without power limits enforced on Intel’s i7-14700K, the CPU will hit its peak temperature (TJ Max) and thermally throttle with even the strongest of air coolers. When the CPU reaches its peak temperature, I’ve measured the CPU package power to determine the maximum wattage cooled to best compare their performance.

I wasn’t expecting a lot out of this cooler, so it is no surprise that it is the worst performing result on this list when you consider that the comparison coolers I’ve also tested are higher-end, more-expensive products.

What is surprising is how closely it performed to Noctua’s original NH-D15, trailing by only 5W! This is very impressive for a single-tower, single-fan cooler.

While the Assassin X didn’t top the charts in terms of thermal performance, it runs nice and quietly. With a maximum volume of 41.9 dBA, the Assassin X 120 R SE runs quieter than all of the nine comparison coolers I’ve tested for this review.

Yes, the chart above starts at 35dBA rather than zero. That’s for a couple key reasons: First, noise level measurements are logarithmic. A person with typical hearing will perceive a doubling of noise for every 10 dBA increase, but the impact can vary from person to person. Subjectively, I feel that a 5dBA increase feels like twice as loud – but I suffer from conditions which can make my ears more sensitive than others.

Secondly, 35dBA was chosen as our “zero” point because it is the lowest level my noise meter can accurately measure.

Thermal results with noise normalized to 38.9 dBA

Finding the right balance between fan noise levels and cooling performance is important. While running fans at full speed can improve cooling capacity to some extent, the benefits are limited and many users prefer a quieter system. With this noise-normalized test, I’ve set noise levels to 38.9 dba. This level of noise is a low volume level, but slightly audible to most people. 

Thermalright’s Assassin X 120 R SE cooled an average of 213W in this scenario, only 5W behind Noctua’s first-generation NH-D15!

165W CPU + 275W GPU results

I’ve recently updated my testing to better represent the scenarios a user might actually encounter in real life usage. The first of these new tests is designed to emulate, though not perfectly, a CPU intensive game with a full GPU load.

Thermalright’s Assassin X 120 R SE gets a bit toasty in this workload, averaging 83C during the course of testing. This is fine for CPUs at their stock speeds, but you wouldn’t want to try overclocking. 

Because of the higher CPU temperature, the Assassin X 120 R SE reaches its maximum noise level of 41.9 dBA – but this is actually quieter than many of the competitors I’ve tested it against, with only Arctic’s Liquid Freezer III AIO running quieter.

110W CPU + 275W GPU results

Our second round of CPU + GPU testing is performed with a lower CPU power limit, and in theory should be similar to games that are moderately intensive for a CPU. The Thermalright Assassin X 120 R SE reached 70C in this scenario, 4C behind Noctua’s NH-D15.

120W Cinebench results

With my previous testing methodology, I used to record the temperatures and noise measurements using a 125W CPU-only test and I would emphasize how temperatures do not matter in this scenario. 

As such, for this section I’m only going to report noise levels – because that’s the only information that really matters for this test. The temperature of the CPU in this scenario is largely irrelevant, but the results for liquid coolers is similar to those reported above in the 110W + GPU tests if you are particularly concerned about this information.

The cooler reached only 38.9 dBA here, a low noise level that shouldn’t bother most folks. Only Arctic’s Liquid Freezer III ran quieter than Thermalright’s Assassin X 120 R SE here.

Conclusion

For users on a strict budget, Thermalright’s Assassin X 120 R SE is probably the best option on the market at the moment. This isn’t a product you’d want to use while overclocking, but for less than $20 USD, it delivers essential cooling performance sufficient for most users, while also keeping noise levels low.