If you are deciding between the Thermalright Peerless Assassin 120 SE CPU Cooler and the Noctua NH-D15 G2 chromax.Black, you are weighing two very different approaches to high end air cooling for your gaming PC. Both use a dual tower layout with two fans to handle modern AMD and Intel CPUs, but one is built to deliver strong cooling at a very accessible level while the other is the more premium choice focused on acoustic refinement and extra thermal headroom.
This comparison is for builders who already know they want air cooling and are trying to match a cooler to their case, RAM and platform. You will see how they differ on size and case fit, fan design and noise, heatpipe and surface area, plus RAM clearance and mounting, so you can choose with confidence for your build in September 2026. For a broader look at cooling options, browse our CPU Cooling category.
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Quick Picks at a Glance
Prime Thermalright Peerless Assassin 120 SE CPU Cooler
Noctua NH-D15 G2 chromax.Black Dual-Tower CPU Air
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Pros
- Excellent cooling performance for its class with dual tower and six heat pipe layout
- Very quiet operation even at full 1550 RPM with PWM control
- Broad support for latest Intel and AMD sockets
- Solid build quality with copper base and aluminum heatsink
- Efficient dual fan setup without the complexity of liquid cooling
Cons
- Tall 155mm height requires a mid tower or larger case, compatibility check is essential
- AMD installation requires the original motherboard backplate which is not included
- Bulky 907g dual tower design can make installation tight in compact builds
The Thermalright Peerless Assassin 120 SE is a dual tower air cooler designed for gamers, enthusiasts and PC builders who want high end cooling without an AIO. It targets users running modern Intel LGA 1700 and 1851 or AMD AM4 and AM5 CPUs who need reliable thermal headroom for gaming and multitasking.
In real world use, the six AGHP copper heat pipes and dual 120mm PWM fans deliver impressive heat dissipation while staying efficient. With up to 66.17 CFM airflow and a max speed of 1550 RPM, it keeps temperatures low under load while maintaining noise at just 25.6 dB for quiet operation.
Build quality is a clear strength thanks to the pure copper base, nickel plated heat pipes and dense aluminum fin stacks joined by reflow welding. The dual TL-C12C fans use a 4 pin PWM connection for precise speed control and the offset tower design helps preserve RAM clearance on most motherboards.
The main drawback is its size, as the 125 x 135 x 155mm footprint demands a spacious case and careful compatibility checks. Installation on AMD systems also requires reusing the original motherboard backplate, which can be inconvenient if it was misplaced.
Overall, the Peerless Assassin 120 SE offers best in class air cooling performance, quiet operation and broad socket support at an accessible point. It is an excellent choice for anyone wanting powerful, reliable CPU cooling without the cost or maintenance of liquid cooling.
Model: Thermalright PA120 SE Dual Tower CPU Cooler
Dimensions: 125 x 135 x 155mm (4.92 x 5.31 x 6.1 inch)
Heat Pipes: 6 x 6mm pure copper with AGHP technology
Fans: 2 x TL-C12C 120mm PWM, 1550 RPM ±10%, 66.17 CFM, 25.6 dB(A), 4-Pin 12V
Compatibility: Intel LGA 115X / 1200 / 1700 / 1851 and AMD AM4 / AM5
Materials: Aluminum fins, pure copper base and heat pipes, metal mounting kit
Weight: 907g
Pros
- Elite air cooling performance that rivals many 240mm and 280mm AIO liquid coolers
- Remarkably quiet at idle and well controlled under full load thanks to advanced G2 fans
- Outstanding Noctua build quality, reliability and attention to detail
- Comprehensive accessories and installer-friendly mounting system
- All-black design finally offers flagship performance without the classic brown color scheme
Cons
- Massive 6.61-inch tall dual-tower footprint requires a large case and RAM clearance planning
- Premium price is higher than many competing air coolers and entry-level AIOs
- Heavy 1810g weight needs careful handling, especially when moving a tower PC
The Noctua NH-D15 G2 chromax.Black is the second generation of Noctua's legendary flagship air cooler, refined for enthusiasts, gamers and workstation users running high-end AMD Ryzen and Intel Core processors. It is built for those who want elite cooling without the complexity or risk of liquid cooling.
In real-world use it delivers outstanding thermal headroom thanks to eight heatpipes, expanded fin surface area and two new NF-A14x25r G2 fans. Users report significant temperature drops compared to previous coolers, with chips like the Ryzen 9 9950X3D and 7800X3D staying well below throttling limits even under sustained stress, all while remaining remarkably quiet.
Build quality is classic Noctua, with dense aluminum fins, polished copper heatpipes and a sleek all-black chromax finish that finally matches modern stealth builds. The SecuFirm2+ mounting system with Torx screws and included NM-SD1 screwdriver makes installation more secure and straightforward, while the offset design improves PCIe and RAM compatibility.
The sheer size is its main trade-off, as the tall dual-tower heatsink demands a spacious case and low-profile RAM for dual-fan clearance. It is also a premium investment, and its weight means extra care is needed when transporting a tower system.
Overall, the NH-D15 G2 chromax.Black sets the benchmark for premium air cooling, combining top-tier performance, near-silent acoustics and exceptional craftsmanship. If your case can accommodate it, it is one of the best long-term cooling investments you can make for a high-performance PC.
Model: NH-D15 G2 chromax.black
Cooling Method: Dual-tower air cooler with 8 heatpipes
Fans: 2x NF-A14x25r G2 140mm PWM, 1500 RPM max, 24.8 dB noise, 155.6 m3/h airflow
Compatibility: AMD AM5, AM4 and Intel LGA1851, LGA1700, LGA1200, LGA115x
Dimensions: 5.98 x 5.91 x 6.61 inches
Weight: 1810g
RAM Clearance: 59mm in single-fan mode, 32mm with both fans
Connector: 4-Pin PWM, 12V, 2.28W
Included: NT-H2 thermal paste, Low-Noise Adaptors, NM-SD1 screwdriver, SecuFirm2+ mounting kit
Warranty: 6-year manufacturer warranty
How They Compare
Cooler Size, Height and Case Compatibility
The Thermalright Peerless Assassin 120 SE CPU Cooler lists its dimensions as 125(L) x 135(W) x 155(H) mm, which is 4.92 x 5.31 x 6.1 inches, with a 155 mm tall dual tower heatsink made from aluminum. The Noctua NH-D15 G2 chromax.Black is a larger class cooler built around two 140 mm fans and 20 percent more surface area than its predecessor, so it occupies more volume above the motherboard and inside the case. When you compare them side by side, the Thermalright is the more compact dual tower, while the Noctua trades a bigger footprint for additional fin area.
For your build, that size difference matters most for case clearance. You should check your case specification for maximum CPU cooler height or radiator clearance and compare it directly against the cooler height before you buy, and follow the manufacturer mounting instructions closely. The 155 mm height of the Thermalright Peerless Assassin 120 SE CPU Cooler fits many mid tower cases, but compact or slim cases may still be tight, and the Noctua NH-D15 G2 chromax.Black with its wider 140 mm fan setup is not ideal for small cases with limited height or narrow CPU cutouts. If you are planning a compact build, our Budget Build Guides can help you match case and cooler size.
Fan Design, Noise and Airflow Control
The Thermalright Peerless Assassin 120 SE CPU Cooler ships with two TL-C12C PWM fans, each 120 x 120 x 25 mm, rated at 1550 rpm plus or minus 10 percent over a 4 pin 12V connection, with up to 66.17 CFM airflow and a noise level at or below 25.6 dB(A). The Noctua NH-D15 G2 chromax.Black uses two state of the art NF-A14x25r G2 140 mm fans that include a speed offset for acoustic fine tuning, plus Low-Noise Adaptors and PWM for automatic speed control. In practice, the Thermalright gives you higher rated maximum airflow from smaller fans spinning faster, while the Noctua leans on larger, slower spinning fans and tuning features to keep noise down under load and near silent at idle.
Both coolers let your motherboard control fan speed through PWM, so you can build a quiet idle and ramp up only when gaming or rendering. Owners commonly report that the Noctua NH-D15 G2 chromax.Black stays very quiet even when the system is stressed, thanks to its fan design and adaptors, while the Thermalright Peerless Assassin 120 SE CPU Cooler is also rated for low noise at its 25.6 dB(A) ceiling but will be more audible as both 120 mm fans approach their 1550 rpm limit. If you pair either cooler with a hot GPU, such as the cards in our top RTX 5070 ti cards for 1440p gaming guide, you will want a case with good front to back airflow so the CPU cooler is not recycling warm air.
Heatpipe Layout, Surface Area and Thermal Headroom
Heatpipe count and fin area set the ceiling for how much heat a dual tower can move away from the CPU. The Thermalright Peerless Assassin 120 SE CPU Cooler uses six 6 mm heat pipes with AGHP technique, described as solving the inverse gravity effect from vertical or horizontal orientation, along with pure copper sintered pipes, a pure copper base and a full electroplating reflow welding process. The Noctua NH-D15 G2 chromax.Black steps up to eight heatpipes and, per the spec sheet, 20 percent more surface area than the previous NH-D15 generation, paired with its new NF-A14x25r G2 fans for improved quiet cooling performance.
What this means for you is a difference in sustained headroom rather than a simple win or loss. The Thermalright Peerless Assassin 120 SE CPU Cooler, with its six heatpipes and dual 120 mm fans, is evaluated as a strong performer for mainstream gaming CPUs and moderate all core loads, while the Noctua NH-D15 G2 chromax.Black with eight heatpipes and extra fin area is assessed as the higher headroom option for long gaming sessions and heavy multi core work where you want lower fan speeds. Neither cooler can guarantee unlimited thermal capacity, you should still follow the CPU maker guidance on power limits and case airflow, and handle installation with anti static precautions.
RAM Clearance, Motherboard Fit and Mounting Experience
RAM and motherboard compatibility often decides which dual tower you can actually live with day to day. The Thermalright Peerless Assassin 120 SE CPU Cooler is designed to leave room for memory modules so installation is unrestricted, which helps if you have tall RGB DIMMs. The Noctua NH-D15 G2 chromax.Black takes a more detailed approach with an offset design and recessed lower fins that clears the top PCIe x16 slot on most current motherboards, offering 59 mm RAM clearance in single fan mode and 32 mm with both fans installed, so you can adjust fan position to fit your memory.
Mounting and platform support also differ. The Thermalright Peerless Assassin 120 SE CPU Cooler supports Intel 115X, 1200, 1700 and 17XX and AMD AM4 and AM5, includes metal fasteners for both platforms, and notes that for AMD you need to use the original motherboard built in backplate which is not included. The Noctua NH-D15 G2 chromax.Black includes NT-H2 thermal paste and a Torx based SecuFirm2+ mounting system with an NM-SD1 screwdriver, and supports AMD AM5 and AM4 as well as Intel LGA1851, LGA1700, LGA1200 and LGA115x. If you are building around a modern AMD system like the one in our ryzen 5 7600 RX 7700 XT 1000 dollar gaming PC amazon build, check the Noctua Compatibility Centre for your exact motherboard and RAM height, and always follow the included instructions for mounting pressure and paste application.
Which One Should You Get
Choose Thermalright Peerless Assassin 120 SE CPU Cooler if you want strong dual tower cooling that respects case and RAM limits without moving to a premium tier. You get a 155 mm tall heatsink, two PWM 120 mm fans rated to 1550 rpm and 66.17 CFM with noise at or below 25.6 dB(A), six 6 mm AGHP heatpipes and broad socket support for Intel 115X, 1200, 1700, 17XX and AMD AM4 and AM5. It is a smart match for 1080p and 1440p gaming builds where value, easy RAM access and wide case compatibility matter more than chasing the last few degrees at minimum noise.
Choose Noctua NH-D15 G2 chromax.Black if you prioritize quiet operation, extra surface area and a refined ownership experience and you are comfortable with the more premium choice. You get eight heatpipes, 20 percent more surface area, two NF-A14x25r G2 140 mm fans with speed offset and Low-Noise Adaptors, an offset recessed fin design with 59 mm RAM clearance in single fan mode and 32 mm with both fans, plus NT-H2 paste and the SecuFirm2+ mounting system with NM-SD1 screwdriver. It is the better fit for high core count Ryzen 9 or Core Ultra and Core i9 systems, larger ATX cases with good cooler height, and builders who want near silent idle with efficient cooling under load.
Who Should Skip Both
These dual tower air coolers are not a good fit if you have a small form factor case with limited CPU cooler height, a very narrow motherboard tray, or tall memory that already conflicts with your current cooler. They are also not ideal for builds that need 240 mm or larger AIO radiator support for aesthetic reasons or for systems where you plan to move the PC frequently and want to avoid the weight and leverage of a large air cooler. In those situations, a low profile air cooler or a compact liquid cooler that matches your case radiator clearance is not the right choice to replace these towers, so check your case manual and motherboard QVL first.
Frequently Asked Questions
Will the Thermalright Peerless Assassin 120 SE fit my case if the Noctua NH-D15 G2 does not?
Often yes, because the Thermalright Peerless Assassin 120 SE CPU Cooler is 155 mm tall with 120 mm fans, while the Noctua NH-D15 G2 chromax.Black uses larger 140 mm fans and more surface area that needs extra height and width. You should still verify your case maximum CPU cooler height and measure RAM height against the Noctua 59 mm single fan and 32 mm dual fan clearances. If your case is under 160 mm cooler height, the Thermalright is usually the safer air cooling option.
Which cooler is quieter for gaming, Thermalright Peerless Assassin 120 SE or Noctua NH-D15 G2 chromax.Black?
Per the spec sheet, the Thermalright is rated at or below 25.6 dB(A) at up to 1550 rpm and 66.17 CFM, while the Noctua emphasizes quiet cooling with NF-A14x25r G2 fans, speed offset and Low-Noise Adaptors. Owners commonly report the Noctua NH-D15 G2 chromax.Black holds lower noise at similar heat loads due to its larger fans and tuning options. Both are PWM controlled, so you can set a quiet fan curve in BIOS for idle and let them ramp only under load.
Do I need different mounting hardware for AMD AM5 versus Intel LGA1700 or LGA1851?
Both coolers support AMD AM4 and AM5 and Intel LGA1700, LGA1851, LGA1200 and LGA115x, but the included parts differ. The Thermalright Peerless Assassin 120 SE CPU Cooler provides metal fasteners for each platform and requires the original AMD motherboard backplate for AM4 and AM5. The Noctua NH-D15 G2 chromax.Black includes its SecuFirm2+ system with Torx mounting and an NM-SD1 screwdriver plus NT-H2 paste, so you have everything in the box for either platform.
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