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Noctua NH-U9S vs Thermalright Assassin X 120R SE V2 CPU Cooler, 4×

Updated August 2026 — Noctua NH-U9S leads on cooling and warranty.

The Noctua NH-U9S offers superior performance and quieter operation, while the Thermalright Assassin X 120R SE V2 is a budget-friendly option with RGB aesthetics.

Why Noctua NH-U9S is better

Cooling Performance

Noctua's fan design provides quieter operation.

Build Quality

Premium materials and 6-year warranty.

Installation

Includes high-end thermal paste.

Why Thermalright Assassin X 120R SE V2 CPU Cooler, 4× is better

Price

Thermalright is significantly cheaper.

RGB Features

Offers customizable RGB lighting.

Height

Slightly taller for better cooling in larger cases.

Overall score

Noctua NH-U9S
85
Thermalright Assassin X 120R SE V2 CPU Cooler, 4×
65

Specifications

SpecNoctua NH-U9SThermalright Assassin X 120R SE V2 CPU Cooler, 4×
Fan SpeedPWM1550 RPM
Noise LevelQuiet25.6 dB(A)
Socket SupportIntel/AMDIntel/AMD
Warranty6 years2 years
Thermal PasteIncludedNot Included

Dimension comparison

Noctua NH-U9SThermalright Assassin X 120R SE V2 CPU Cooler, 4×

Introduction to CPU Coolers

In the realm of CPU coolers, the Noctua NH-U9S and the Thermalright Assassin X 120R SE V2 stand out as two prominent options. The Noctua NH-U9S is priced at $69.95, while the Thermalright Assassin X 120R SE V2 comes in significantly cheaper at $16.59, making it about 76% less expensive. This price difference invites a closer examination of their features and performance to determine which cooler might be the better choice for your build.

Design and Compatibility

The Noctua NH-U9S boasts a compact single-tower design that is only 125mm high, making it ideal for HTPCs, ITX, and small form factor builds. This design ensures that it does not overhang RAM or PCIe slots on most motherboards, promoting a clean and efficient layout. In contrast, the Thermalright Assassin X 120R SE V2 features a slightly larger 148mm height, which may limit compatibility with smaller cases but allows for enhanced cooling capabilities. Both units are designed with compatibility in mind, supporting a variety of Intel and AMD sockets, but the NH-U9S’s lower profile may appeal to those with tighter spaces.

Cooling Performance

When it comes to cooling performance, the Noctua NH-U9S is recognized for its strong cooling capabilities, aided by its highly optimized NF-A9 92mm fan. This fan operates quietly and efficiently, providing low-noise operation. On the other hand, the Thermalright Assassin X 120R SE V2 utilizes a 120mm RGB PWM fan that spins at 1550 RPM and boasts an airflow of 66.17 CFM, with a noise level of 25.6 dB(A). While both coolers promise effective cooling, the Noctua’s fan design may provide a quieter experience, which is particularly beneficial for users who prioritize a silent PC environment.

Installation and Setup

Installation can often be a deciding factor for many builders. The Noctua NH-U9S includes a SecuFirm2 mounting system that simplifies the installation process for both Intel and AMD platforms. Additionally, it comes with high-end NT-H1 thermal paste, which is known for its excellent thermal conductivity. Meanwhile, the Thermalright Assassin X 120R SE V2 provides detailed installation instructions and includes various mounting plates for compatibility with different CPU sockets. While both products are designed for easy installation, the Noctua’s inclusion of thermal paste may save users an extra step and provide immediate performance benefits.

Noise Levels

Noise levels are a critical aspect of any CPU cooler, especially for users looking for a quiet computing experience. The Noctua NH-U9S is designed for ultra-quiet operation, thanks to its low-noise adaptor and optimized fan design. In comparison, the Thermalright Assassin X 120R SE V2, with its PWM fan, operates at a noise level of up to 25.6 dB(A). Although this is still relatively quiet, it may not match the Noctua’s acoustic performance. For those who prioritize a silent PC, the NH-U9S may be the more appealing choice.

Aesthetics and RGB Features

Aesthetics play a significant role in many PC builds, and the Thermalright Assassin X 120R SE V2 features RGB lighting, which allows for customization and visual appeal. In contrast, the Noctua NH-U9S opts for a more traditional brown and beige color scheme that is characteristic of Noctua’s brand. While the NH-U9S is aesthetically pleasing in its own right, users who want to add a splash of color to their build may find the RGB features of the Thermalright cooler more attractive.

Price and Value

The price difference between the two coolers is substantial, with the Noctua NH-U9S retailing at $69.95 and the Thermalright Assassin X 120R SE V2 at $16.59. This makes the Thermalright cooler about 76% cheaper, which is a significant factor for budget-conscious builders. However, the NH-U9S justifies its higher price with its premium build quality, quieter operation, and a reputation for reliability. Therefore, while the Thermalright offers excellent value for its price, the Noctua may be worth the investment for users seeking high performance and durability.

Which should you buy?

Choosing between the Noctua NH-U9S and the Thermalright Assassin X 120R SE V2 ultimately comes down to your specific needs and budget. If you are looking for a compact cooler with premium performance and quieter operation, the Noctua NH-U9S is an excellent choice, albeit at a higher price point. Conversely, if you are seeking a budget-friendly option that still delivers solid cooling performance and RGB aesthetics, the Thermalright Assassin X 120R SE V2 is a fantastic option. Consider your priorities, such as noise levels, aesthetics, and installation ease, before making your final decision.