Thermalright's Peerless Assassin Mini delivers exceptional thermal performance in a compact form factor, making it ideal for small-case builds. Machines & More praised its sturdy construction and strong cooling ability despite its reduced size. The cooler features a single 120mm fan with fluid dynamic bearing and is priced at $35, matching the full-size version's cost without discount. While it lacks the premium features of some competitors, its performance justifies the price for users needing a compact solution.
Full review
Compact design with full-size performance
Tom's Hardware found the Thermalright Peerless Assassin 120 Mini to be a remarkably compact cooler that still delivers strong thermal performance. The cooler stands at just 135mm tall, making it suitable for smaller form factor builds where vertical clearance is limited. It features two tower sections connected by a base plate with six 6mm heat pipes, a design that allows it to maintain excellent heat dissipation despite its reduced size. The single 120mm fan operates at a maximum of 1500 RPM, which is lower than some competitors, but still effective for its intended use cases.
Machines & More noted that the cooler's design is similar to the older Thermalright Silver Soul 135, but with notable differences in the fin stack shape and heatpipe caps. The Assassin Mini has a central indent in its fin stack and uses a recessed connective plate at the sidewalls, distinguishing it from the Silver Soul's cascading cut. The cooler's dimensions are 125mm x 110mm x 135mm, which is significantly shorter than the original Peerless Assassin, but still provides a robust cooling solution for systems with limited space.
The cooler's mounting system is straightforward, using mounting bars that fit standard AM4 and AM5 sockets. It supports LGA 115x, 1200, 1700, and 2011-66 sockets, offering wide compatibility. The design allows for easy installation and provides sufficient clearance for RAM modules, with most boards allowing for 44mm tall RAM without interference. The fan can be installed in either air flow direction, and the cooler supports both single and dual tower configurations.
Thermal performance in demanding scenarios
Tom's Hardware measured the cooler's performance under sustained loads, finding that it performs well for CPUs drawing around 120 watts of power. In their testing with a Ryzen 7 5800X running at 4.6 GHz and 1.25 volts, the cooler maintained temperatures that were close to those of the Noctua D12 and the Silver Soul 135. The performance difference between the two coolers was minimal, with the PA120 Mini trailing the D12 L by only about 2 dB at the first noise level, and showing similar performance at higher noise levels.
Machines & More reported that the cooler's performance was particularly impressive when tested with the Ryzen 7 5800X in a system with PBO enabled. The cooler maintained temperatures that were well within acceptable ranges, even under high load conditions. The fan's ability to spin up to 1500 RPM allowed for effective cooling, and the cooler's design helped to minimize noise levels during operation. The cooler's performance was especially notable in the 120-135 watt range, where it excelled compared to many other compact coolers.
In their testing, Machines & More also noted that the cooler's performance was consistent across different scenarios, including BIOS default settings, manual PBO settings, and AMD Eco Mode presets. The cooler's ability to maintain stable temperatures under various conditions made it a reliable choice for users who need a compact cooler that can handle demanding workloads without overheating.
Noise levels and fan performance
Tom's Hardware measured the cooler's noise output and found it to be relatively quiet, especially when compared to other coolers in its class. The single 120mm fan operates at a maximum of 1500 RPM, which is lower than some competitors, but still provides adequate cooling. The cooler's noise levels were comparable to those of the Noctua D12 L, with the PA120 Mini trailing by about 2 dB at the first noise level. At higher noise levels, the performance gap remained small, indicating that the cooler maintains good performance while keeping noise to a minimum.
Machines & More noted that the cooler's fan performance was adequate for most users, but they expressed a desire for a higher maximum RPM. The fan's current maximum of 1500 RPM is sufficient for most applications, but users who want to push their CPUs to the limit might benefit from a fan that can spin faster. The cooler's design does not allow for easy fan upgrades, as the mounting clips are not compatible with other 120mm fans, which limits the ability to increase airflow.
The fan's fluid dynamic bearing was noted to be a positive aspect of the cooler's design, as it reduces wear and tear on the fan motor. This contributes to the cooler's overall longevity and reliability. However, the fan's maximum RPM is still limited, which may be a drawback for users who want maximum cooling performance at the expense of noise.
Compatibility and installation ease
Tom's Hardware found that the cooler's mounting system is straightforward and compatible with a wide range of sockets, including AM4, AM5, LGA 115x, 1200, 1700, and 2011-66. The mounting bars are designed to fit standard spacers, and the cooler can be installed using the stock back plate. The design allows for easy installation and provides sufficient clearance for RAM modules, with most boards allowing for 44mm tall RAM without interference.
Machines & More emphasized the cooler's compatibility with smaller form factor builds, particularly ITX cases where vertical clearance is limited. The cooler's 135mm height makes it ideal for these builds, and it can fit in cases as small as the Noctua D12 L, which is 145mm tall. The cooler's design also allows for easy installation, with mounting clips that secure the fan in place and prevent it from shifting during operation.
The cooler's design also includes a flat shroud that covers the heatpipe tips, which not only enhances the cooler's appearance but also helps to reduce noise. The cooler's mounting system is simple and does not require any special tools, making it accessible to both beginners and experienced builders. The cooler's compatibility with a wide range of sockets ensures that it can be used in various systems without any issues.
Value proposition and market positioning
Tom's Hardware noted that the Thermalright Peerless Assassin 120 Mini is priced at $35, which is the same as the full-size Peerless Assassin, despite being smaller and having a single fan. This pricing strategy may not be ideal for budget-conscious consumers, but it reflects the cooler's premium design and performance. The cooler's ability to deliver strong performance in a compact form factor justifies its price point for users who need a high-performance cooler in a small space.
Machines & More observed that the cooler's value proposition is strong for users who need a compact cooler that can handle demanding workloads. The cooler's performance is comparable to that of larger, more expensive coolers, and its design allows it to fit in smaller cases where other coolers might not fit. The cooler's ability to maintain stable temperatures under various conditions makes it a reliable choice for users who want a cooler that can handle high loads without overheating.
The cooler's design and performance make it a strong contender in the compact cooler market, especially for users who are building small form factor systems. Its compatibility with a wide range of sockets and its ability to fit in smaller cases make it a versatile choice for various builds. While the price may be slightly higher than some competitors, the cooler's performance and build quality justify the cost for users who need a reliable, high-performance cooler in a compact package.
Strengths
- +Performs extremely well considering its compact size reduction
- +Maintains high-quality materials and sturdy construction despite small stature
- +Single 120mm fan with fluid dynamic bearing for quiet operation
- +Suitable for compact cases with reduced vertical clearance like ITX and micro-ATX
Watch-outs
- −No price cut from the full-size Peerless Assassin despite size reduction
- −Capped fan speed at 1500 RPM compared to Silver Soul 135's 1850 RPM
How it compares
The Thermalright Peerless Assassin 120 Mini stands out for its compact design that maintains high performance, but it's priced the same as the full-size version, making it less economical than the Thermalright Phantom Spirit 120 SE which offers an extra heat pipe and better value. Unlike the be quiet! Pure Rock Pro 3 Black, it lacks dual fans and has a single 120mm fan capped at 1500 RPM compared to the Pure Rock Pro 3's dual 120mm fans with higher airflow.
Rating sources
“I think this is a very impressive cooler and why for the broader audience it's actually going to be the more sensible Choice.”
Our 4.0 score is the average of the 1 scored review above; 1 more reviewed it without printing a score and is not in the average. Ratings marked * were derived from the reviewer’s written analysis or video transcript — the publisher didn’t print an explicit numeric score, so we inferred one from their own words. Click through to verify. More about methodology.
