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Noctua NH-L12S vs Thermalright Assassin X120 Refined SE CPU Air

Updated July 2026 — Noctua NH-L12S wins on depth and width, Thermalright Assassin X120 Refined SE CPU Air wins on height and heat pipes.

The Noctua NH-L12S offers superior build quality and cooling performance, while the Thermalright Assassin X120 is a budget-friendly option. Choose based on your priorities.

Why Noctua NH-L12S is better

Cooling Performance

NH-L12S has optimized fan for quieter operation

Build Quality

NH-L12S features premium materials and a long warranty

Compact Design

NH-L12S is shorter, ideal for compact builds

Why Thermalright Assassin X120 Refined SE CPU Air is better

Price

Assassin X120 is significantly cheaper

Weight

Assassin X120 is lighter than NH-L12S

Compatibility

Assassin X120 supports a wide range of sockets

Overall score

Noctua NH-L12S
85
Thermalright Assassin X120 Refined SE CPU Air
65

Specifications

SpecNoctua NH-L12SThermalright Assassin X120 Refined SE CPU Air
Noise Level≤25 dB(A)≤25.6 dB(A)
Warranty6 yearsNot specified
Fan SpeedPWM1550 RPM
Thermal PasteNT-H1Not included
Socket SupportMultipleMultiple

Dimension comparison

Noctua NH-L12SThermalright Assassin X120 Refined SE CPU Air

Overview of the Noctua NH-L12S and Thermalright Assassin X120 Refined SE

The Noctua NH-L12S is a premium low-profile CPU cooler priced at $74.95, while the Thermalright Assassin X120 Refined SE is significantly more affordable at $17.90. This major price difference of about 77% raises an important question: what do you get for your money with the more expensive Noctua product?

The Noctua NH-L12S boasts a compact design ideal for ITX and HTPC systems, offering optimized cooling performance with its NF-A12x15 120mm PWM fan. In contrast, the Thermalright Assassin X120, equipped with four heat pipes and an aluminum heatsink cover, also aims to provide effective cooling but at a much lower price point.

Design and Build Quality

The Noctua NH-L12S features a total height of 70mm, making it an outstanding choice for compact builds. Its premium-quality construction is backed by a six-year manufacturer’s warranty, ensuring durability. The NH-L12S is designed for easy installation on various Intel and AMD sockets, reflecting Noctua's commitment to user-friendly products.

On the other hand, the Thermalright Assassin X120 measures 148mm in height and weighs 0.645kg, which makes it bulkier than the Noctua. However, it utilizes aluminum for its heatsink, providing a sturdy build. The design is functional and features four heat pipes that apply AGHP technology, which seeks to address issues related to inverse gravity effects during operation.

Cooling Performance

Cooling performance is critical in any CPU cooler, and the Noctua NH-L12S excels in this area. Its NF-A12x15 fan, optimized for low noise levels, contributes to its quiet operation, making it suitable for environments where sound is a concern. The performance is complemented by the included high-end NT-H1 thermal paste, which enhances thermal conductivity.

The Thermalright Assassin X120 also emphasizes quiet operation, with its TL-C12C PWM fan capable of generating air flow up to 66.17 CFM while maintaining a noise level of 25.6 dB(A). While it may not match the premium cooling performance of the Noctua, the Thermalright cooler offers a satisfactory balance of efficiency and noise reduction for a budget option.

Compatibility and Installation

Compatibility is a strong suit for both products. The Noctua NH-L12S supports a wide range of Intel sockets, including LGA1851, LGA1700, and LGA1200, as well as AMD AM5 and AM4. Its SecuFirm2 mounting system simplifies installation, making it accessible even for novice builders.

Similarly, the Thermalright Assassin X120 is compatible with an array of Intel and AMD sockets, including LGA 1150, 1151, 1155, and AM4/AM5. The cooler comes equipped with metal fasteners that facilitate better installation, though the larger size may pose some challenges in compact cases.

Noise Levels

When it comes to noise levels, the Noctua NH-L12S is designed to operate quietly, making it an excellent choice for users who prioritize a silent PC experience. The PWM fan allows for automatic speed control, ensuring that the cooler operates efficiently under varying loads while keeping noise to a minimum.

The Thermalright Assassin X120, while also designed for low noise, has a maximum noise level of 25.6 dB(A). Although this is relatively quiet, it may not match the ultra-quiet performance that Noctua is known for. Users looking for the quietest operation possible may lean towards the NH-L12S.

Price Point Analysis

The price difference between the Noctua NH-L12S and the Thermalright Assassin X120 is substantial, with the Noctua priced at $74.95 and the Thermalright at $17.90. This means that the NH-L12S is about 317% more expensive than its competitor.

While the Thermalright cooler offers a budget-friendly solution, the Noctua cooler's higher price reflects its premium features, build quality, and warranty. Buyers must consider whether these additional benefits justify the higher cost, depending on their specific cooling needs and budget constraints.

Brand Reputation and Warranty

Noctua has built a strong reputation in the cooling industry, known for its high-quality products and excellent customer support. The NH-L12S is backed by a six-year warranty, which speaks volumes about the brand's confidence in its product’s durability and performance.

Thermalright, with over 20 years in the market, is also a respected name, particularly in the gaming and PC building community. However, the lack of a specified warranty period may leave some users questioning the long-term reliability of the Assassin X120. This factor could influence a buyer's choice when considering long-term investment in a CPU cooler.

Which should you buy?

Choosing between the Noctua NH-L12S and the Thermalright Assassin X120 ultimately depends on your specific needs and budget. The Noctua NH-L12S offers superior build quality, exceptional cooling performance, and a long warranty, making it ideal for users who prioritize these aspects and are willing to invest more for them.

Conversely, if you're looking for a more economical option that still provides decent performance and compatibility, the Thermalright Assassin X120 is a viable choice. It caters well to budget-conscious consumers without sacrificing efficiency. In summary, if top-tier performance and longevity are your priorities, go for the Noctua NH-L12S. If you need a reliable cooler at a fraction of the price, the Thermalright Assassin X120 is the way to go.