This review analyzes published product information. We have not performed detailed research of this unit.
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The Thermalright Peerless Assassin 120 SE pairs a dual-tower heatsink with two 120mm PWM fans. For a gaming PC upgrade, the important question is not simply whether its socket appears on a compatibility list: the complete cooler must also fit beside the memory, beneath the side panel and onto the available mounting hardware.
The exact configuration here uses two TL-C12C fans and six 6mm heat pipes. It offers a clearly identified mounting and cooling layout, but the listing leaves several installation details unresolved. Those gaps matter particularly when upgrading an assembled system rather than planning around an empty motherboard.
The PA120 SE configuration at a glance
| Item | Listed specification |
|---|---|
| Cooler model | Thermalright PA120 SE / Peerless Assassin 120 SE |
| Layout and dimensions | Dual tower; 125 × 135 × 155mm, length × width × height |
| Heatsink and base | Aluminum heatsink; pure copper base |
| Heat pipes | Six 6mm pure copper sintered pipes with AGHP technology |
| Fans | Two TL-C12C PWM fans, each 120 × 120 × 25mm |
| Fan electrical connection | 4-pin, 12V |
| Listed fan speed | 1550rpm ±10% |
| Listed airflow and noise | 66.17 CFM maximum; noise level ≤25.6 dB(A) |
| Socket support in compatibility details | Intel 115X, 1200, 1700/17XX; AMD AM4 and AM5 |
| Additional title claim | Intel LGA1851 appears in the title but not the detailed compatibility list |
| AMD installation requirement | Original motherboard backplate required; not included with the cooler |
Start with the case, then check the memory area
The listed 155mm height is the first screening measurement. Compare it with your case manufacturer’s permitted CPU-cooler height, not the external width of the enclosure. A specification that only just matches deserves closer inspection: the supplied evidence does not explain the measurement conditions or give an allowance for changes to fan placement.
The 125 × 135mm footprint also deserves attention. A socket match alone does not establish clearance around nearby motherboard components. Before removing an existing cooler, check the board layout, memory position and any substantial heatsinks around the socket against the proposed installation area.
Thermalright’s listing describes the fan arrangement as leaving room for memory, but it provides no numerical RAM-clearance limit. That is not enough to promise compatibility with a particular tall memory kit. Look for a configuration-specific clearance drawing or confirmation for your combination of motherboard and DIMMs. If a proposed installation involves raising a fan, verify both that the mounting arrangement permits it and that the resulting height remains inside the case limit. Neither adjustment range nor adjusted total height is supplied here.
Socket support is not the whole mounting story
The detailed compatibility section identifies Intel 115X, 1200 and 1700/17XX alongside AMD AM4 and AM5. It also says platform-specific mounting plates or fasteners are supplied. That makes these sockets the clearest starting point for checking suitability, although buyers should still confirm the hardware accompanying their exact package.
LGA1851 needs extra caution. It is named in the listing title, but the more detailed compatibility section does not repeat it. That discrepancy is not proof of incompatibility; it is a reason to obtain explicit confirmation of LGA1851 support and the required mounting parts before committing to that installation.
For AMD systems, the original motherboard backplate is a stated requirement and is not included with this cooler. This is especially important when replacing an older cooler whose installation may have involved different hardware. Locate the original backplate before dismantling the PC. The supplied listing does not provide a full illustrated installation sequence, so it cannot settle access requirements or every mounting step in advance.
Two PWM fans require an electrical plan
Both supplied TL-C12C fans are specified as 12V units with 4-pin PWM connections. Check your motherboard manual for appropriate fan headers, their control settings and their electrical limits. The evidence does not state fan current draw or confirm whether a splitter is included. Consequently, it does not establish that both fans can safely share any particular header, nor that the package contains everything needed for your preferred wiring arrangement.
The listed speed is 1550rpm with a ±10% tolerance. The maximum airflow and noise figures are seller specifications, not measured results from this review. They do not tell you how the complete cooler will sound in your enclosure, and the listing does not provide a minimum speed or full control range. Treat PWM support as a control feature rather than a guarantee of quiet operation under every workload.
What the cooling hardware does—and does not—establish
The aluminum dual-tower heatsink, copper base and six copper heat pipes describe the cooler’s construction. Thermalright also attributes improved handling of orientation-related heat-pipe effects to its AGHP technology. That remains a manufacturer claim here; the supplied material does not include comparative testing across mounting orientations.
There are no CPU-specific temperature results, sustained-power limits or gaming measurements in the evidence. It therefore cannot justify a promise that this cooler will meet a particular temperature or acoustic target on your processor. When replacing a working cooler, look for relevant independent testing before assuming this configuration represents a meaningful thermal upgrade. Our gaming CPU cooler guide provides a broader starting point for considering cooler choices.
Frequently asked questions
What are the cooler’s overall dimensions?
The PA120 SE is listed as 125 × 135 × 155mm, with length, width and height given in that order. The 155mm height should be compared with the case manufacturer’s permitted CPU-cooler height. The 125 × 135mm footprint should also be checked against the motherboard layout, nearby heatsinks and memory position before installation.
Does the package include an AMD motherboard backplate?
No, the article states that the original AMD motherboard backplate is required and is not included with the cooler. This matters when replacing an older cooler, because the needed backplate may already be absent or difficult to access. Locate the original backplate before dismantling the PC, particularly for an AM4 or AM5 installation.
Is LGA1851 support confirmed by the detailed specifications?
No, LGA1851 appears in the listing title but not in the detailed compatibility list. The detailed list identifies Intel 115X, 1200 and 1700/17XX, plus AMD AM4 and AM5. The discrepancy does not establish incompatibility, but buyers should obtain explicit confirmation of LGA1851 support and the required mounting parts before proceeding.
Can the two fans be connected to one motherboard header?
The article does not establish that both fans can safely share any particular motherboard header. Each TL-C12C fan is listed with a 4-pin, 12V PWM connection, but fan current draw is not provided and the listing does not confirm that a splitter is included. Check the motherboard manual for header limits and control settings.
Does this article provide CPU temperature or noise results?
No, this article does not provide CPU-specific temperature results, sustained-power limits or gaming measurements. The listed maximum airflow and noise level are seller specifications rather than measurements from this review, and they do not show how the complete cooler will perform in a particular enclosure. Independent testing is needed before assuming a thermal or acoustic target.
Verdict: a candidate worth checking carefully
The Peerless Assassin 120 SE is worth considering when your build accommodates its listed dimensions, its socket is supported and the necessary mounting and fan connections are available. Its dual PWM fans and specified heat-pipe construction give buyers concrete hardware to evaluate. Unquantified RAM clearance, incomplete electrical-accessory information and the LGA1851 listing discrepancy are the principal reasons to verify fit rather than assume it. The specifications support a compatibility shortlist, not a tested performance verdict.
Sources: Supplied Thermalright Peerless Assassin 120 SE retailer listing. Dimensions, construction, compatibility and fan figures above are attributed to that listing.
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