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Noctua NH-U9S vs Thermalrlght Peerless Assassin 120 SE CPU Air

Updated August 2026 — Noctua NH-U9S wins on warranty, Thermalrlght Peerless Assassin 120 SE CPU Air wins on cooling and design.

The Noctua NH-U9S excels in quiet operation and build quality, while the Thermalrlght Peerless Assassin 120 SE offers superior cooling performance at a lower price.

Why Noctua NH-U9S is better

Price

Noctua is more expensive.

Noise

Noctua operates quieter.

Warranty

Noctua has a longer warranty.

Why Thermalrlght Peerless Assassin 120 SE CPU Air is better

Cooling

Thermalrlght has better cooling performance.

Price

Thermalrlght is significantly cheaper.

Fan Size

Thermalrlght has larger fans for better airflow.

Overall score

Noctua NH-U9S
85
Thermalrlght Peerless Assassin 120 SE CPU Air
90

Specifications

SpecNoctua NH-U9SThermalrlght Peerless Assassin 120 SE CPU Air
Cooling TypeAirAir
Fan RPMMax 2000Max 1550
AirflowN/A66.17 CFM
Noise Level≤22.4 dB(A)≤25.6 dB(A)
Warranty6 yearsN/A

Dimension comparison

Noctua NH-U9SThermalrlght Peerless Assassin 120 SE CPU Air

Overview of Coolers

In the realm of CPU coolers, performance and compatibility are paramount. The Noctua NH-U9S and the Thermalrlght Peerless Assassin 120 SE are two distinct options with different strengths and price points. The Noctua NH-U9S is priced at $69.95, while the Thermalrlght Peerless Assassin 120 SE offers a more budget-friendly option at $32.90, making it about 53% cheaper than its competitor.

Design and Aesthetics

When it comes to design, the Noctua NH-U9S features a compact single-tower design, which is ideal for small form factor builds and HTPCs. Its height of only 125mm ensures that it does not overhang RAM or PCIe slots on most motherboards. The Thermalrlght Peerless Assassin 120 SE, on the other hand, has a dual-tower design that stands 155mm tall. While it offers a more robust cooling solution, its larger size may pose compatibility issues in tighter cases. The Noctua's characteristic brown color scheme may not appeal to everyone, while the Thermalrlght's anodized brushed black top cover presents a sleek look.

Cooling Performance

Cooling efficiency distinguishes these two coolers significantly. The Noctua NH-U9S uses a highly optimized NF-A9 92mm fan, which operates quietly and efficiently, ideal for users who prioritize low noise levels. In contrast, the Thermalrlght Peerless Assassin 120 SE boasts dual 120mm TL-C12C PWM fans, providing high airflow performance and rated airflow of 66.17 CFM. This dual-fan setup combined with six heat pipes suggests superior thermal performance, making it more suitable for users with high-performance CPUs that produce more heat.

Installation and Compatibility

Installation ease is another critical factor in choosing a CPU cooler. The Noctua NH-U9S comes with a SecuFirm2 mounting system, facilitating straightforward installation across various Intel and AMD sockets, including LGA1700 and AM4. The Thermalrlght Peerless Assassin 120 SE features an innovative SS2 install system, enhancing contact with the CPU for efficient heat exchange. However, it requires the original motherboard's built-in backplate for installation on AM4 and AM5 motherboards, which may complicate setup for some users.

Noise Levels

Noise performance is often a deciding factor for PC builders. The Noctua NH-U9S is well-regarded for its quiet operation due to its low-noise adaptor and optimized fan design. This cooler is ideal for users looking to build silent systems. On the other hand, while the Thermalrlght Peerless Assassin may generate more noise due to its higher airflow capacity, it maintains a rated noise level of ≤25.6 dB(A), which is relatively quiet for a cooler in its class. Users prioritizing silence may lean towards the Noctua, but those seeking performance might accept a bit more noise.

Build Quality and Warranty

Build quality can reflect the longevity and reliability of CPU coolers. The Noctua NH-U9S is backed by a six-year manufacturer’s warranty, a testament to its quality and durability. It includes high-end NT-H1 thermal paste, ensuring optimal thermal conductivity. The Thermalrlght Peerless Assassin 120 SE, while featuring robust materials like aluminum and copper, does not specify a warranty duration in the provided data. This lack of long-term assurance could be a consideration for users who prioritize longevity in hardware.

Price Comparison

Pricing is a crucial determinant when evaluating these two CPU coolers. The Noctua NH-U9S retails at $69.95, while the Thermalrlght Peerless Assassin 120 SE is significantly more affordable at $32.90. This price difference makes the Thermalrlght cooler approximately 53% cheaper than the Noctua cooler. For budget-conscious consumers, the Thermalrlght offers substantial savings without sacrificing essential performance features, making it a compelling choice for many users.

Which should you buy?

Ultimately, the choice between the Noctua NH-U9S and the Thermalrlght Peerless Assassin 120 SE boils down to individual needs and preferences. If you require a compact cooler for a small build with an emphasis on quiet operation, the Noctua is an excellent choice with its renowned build quality and quiet performance. However, if budget and superior cooling performance are your priorities, the Thermalrlght's dual-fan design and significantly lower price make it a formidable option. Consider your specific requirements to make the best decision for your setup.