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Noctua NH-L9i-17xx vs Thermalright Peerless Assassin 120 Mini Black CPU

Updated August 2026 — Noctua NH-L9i-17xx wins on build quality and warranty, Thermalright Peerless Assassin 120 Mini Black CPU wins on compatibility.

The Noctua NH-L9i-17xx excels in quiet performance and build quality, while the Thermalright Peerless Assassin 120 Mini offers great value for budget-conscious buyers.

Why Noctua NH-L9i-17xx is better

Cooling Performance

Noctua's fan design provides quieter operation.

Build Quality

Noctua has a 6-year warranty.

Size Compatibility

Noctua's low-profile design fits more compact cases.

Why Thermalright Peerless Assassin 120 Mini Black CPU is better

Price

Thermalright is cheaper by 17%.

Airflow

Thermalright's larger fan provides higher airflow.

Versatility

Thermalright supports more CPU sockets.

Overall score

Noctua NH-L9i-17xx
85
Thermalright Peerless Assassin 120 Mini Black CPU
75

Specifications

SpecNoctua NH-L9i-17xxThermalright Peerless Assassin 120 Mini Black CPU
Fan Type92mm120mm
Warranty6 yearsN/A
Cooling TechNF-A9x14AGHP
Max RPMN/A1500
CompatibilityLGA1700/1851LGA1150/1700/AM4

Dimension comparison

Noctua NH-L9i-17xxThermalright Peerless Assassin 120 Mini Black CPU

Overview of the Noctua NH-L9i-17xx and Thermalright Peerless Assassin 120 Mini

The Noctua NH-L9i-17xx and Thermalright Peerless Assassin 120 Mini are both efficient CPU coolers designed to enhance thermal performance in compact builds. The Noctua unit is priced at $49.95, while the Thermalright cooler is available for $34.39, making it about 17% cheaper than its competitor. This price difference may influence buyers looking for budget-friendly options without sacrificing performance.

Cooling Performance

Cooling performance is crucial when selecting a CPU cooler, and both models are designed to meet different user needs. The Noctua NH-L9i-17xx features a renowned NF-A9x14 slim 92mm fan which ensures low noise levels while delivering effective cooling. On the other hand, the Thermalright Peerless Assassin 120 Mini boasts 6 heat pipes and a powerful 120mm PWM fan that operates at a maximum speed of 1500 RPM, providing excellent airflow with a maximum noise level of 25.6dB(A). Depending on your cooling requirements, one may be better suited than the other.

Size and Compatibility

When it comes to size and compatibility, the Noctua NH-L9i-17xx excels with its low-profile design, measuring only 37mm in height. This makes it ideal for compact HTPC and Small Form Factor (SFF) cases, assuring complete RAM and PCIe compatibility with various motherboard types. In contrast, the Thermalright Peerless Assassin 120 Mini has a larger footprint, measuring 125mm x 110mm x 135mm. While it still fits in many cases, its larger size may not be compatible with all compact builds.

Installation Process

Both coolers prioritize user-friendly installation, but they approach it differently. The Noctua NH-L9i-17xx includes the SecuFirm2 mounting system specifically designed for easy setup on Intel LGA1700 and LGA1851 CPUs. Meanwhile, the Thermalright Peerless Assassin 120 Mini offers a versatile mounting kit compatible with various Intel and AMD sockets, including LGA1150, LGA1700, and AM4. While both coolers are designed for easy installation, the Noctua's dedicated system for Intel CPUs may make it simpler for users with those specific platforms.

Build Quality and Warranty

Build quality is a significant factor for many consumers, and here, Noctua has a reputation for excellence. The NH-L9i-17xx is backed by a 6-year manufacturer’s warranty, reflecting the brand's confidence in its durability and performance. Conversely, while the Thermalright Peerless Assassin 120 Mini is also built with care, specific warranty details are not provided, which could be a consideration for some buyers. The assurance of longevity from Noctua may sway users willing to invest more initially.

Noise Levels

Noise levels are a common concern among PC builders, especially in quiet environments. The Noctua NH-L9i-17xx is designed to operate whisper-quiet at idle, thanks to its low-noise adaptor and efficient fan design. In contrast, the Thermalright Peerless Assassin 120 Mini, while still relatively quiet with a maximum noise level of 25.6dB(A), may not achieve the same level of silence as the Noctua under load. This difference could be crucial for users prioritizing a quiet computing experience.

Brand Reputation

Brand reputation plays a vital role in consumer decisions, and both Noctua and Thermalright have established themselves as reputable names in the cooler market. Noctua is widely recognized for its high-quality products and has received over 200 awards and recommendations from international hardware websites. Meanwhile, Thermalright has a solid background with over 20 years of experience and a strong presence in the cooler market. While both brands are respected, Noctua’s accolades may provide extra reassurance for buyers.

Which should you buy?

Choosing between the Noctua NH-L9i-17xx and the Thermalright Peerless Assassin 120 Mini depends largely on your specific needs and budget. If you’re looking for a compact, low-profile cooler that excels in quiet performance and build quality, the Noctua NH-L9i-17xx is worth the investment at $49.95. However, if budget is a priority and you require solid cooling performance with a versatile compatibility range, the Thermalright Peerless Assassin 120 Mini at $34.39 offers excellent value. Ultimately, both coolers have their strengths, making them suitable for different types of users and setups.