Peerless Assassin 120 SE vs Liquid Freezer III Pro 280: choose the layout first
Compare this dual-tower air cooler with the exact ARCTIC 280mm AIO: RAM clearance, radiator stack, mounting position and maintenance tradeoffs.
The air cooler uses clearance above the CPU and memory. The AIO moves much of that demand to a radiator position, where its 65mm radiator-and-fan stack needs checking. Neither product’s format proves a temperature or noise result in your case. Choose a physically viable arrangement, then examine evidence for the CPU load and noise target.
Choose around your situation
Thermalright Peerless Assassin 120 SE
Consider the Peerless Assassin when a 155mm heatsink and the installed fan position fit. Check the RAM underneath the front fan; moving that fan can increase the actual height.
ARCTIC Liquid Freezer III Pro 280 (ACFRE00179A)
Consider the Liquid Freezer III Pro 280 when a compatible 280mm mount can accommodate the complete stack and routing. Check the pump’s motherboard compatibility guidance as well as radiator size.
What changes between these exact parts
These are published specifications. The last column explains how they affect the selection; it is not a benchmark result.
Scroll across the table to compare both models and the practical implications.
| Check | Thermalright Peerless Assassin 120 SE | ARCTIC Liquid Freezer III Pro 280 (ACFRE00179A) | What it means for your build |
|---|---|---|---|
| Cooling arrangement | Dual-tower air | 280 mm liquid AIO | The space requirement moves; it does not disappear. |
| Main recorded dimension | 155 mm heatsink height | 317 × 138 × 38 mm radiator | Installed fan positions and surrounding components must be included. |
| Fan arrangement | Two 120 mm fans | Two 27 mm-thick 140 mm fans | The ARCTIC assembly totals 65mm at the radiator. |
| Fit checks | Socket, RAM and side panel | Socket, pump, radiator, tubes and headers | A matching CPU socket is only one part of the installation. |
Worked decision: a top radiator above tall memory
A case advertising 280mm radiator support may impose a height or thickness condition at the top.
Read the exact case position table. Compare the 65mm stack and 138mm radiator width with the space above the motherboard and RAM.
If the top location conflicts, check whether a front mount reduces GPU clearance or interferes with tubes and drive mounts. Do not assume another position preserves all maxima.
Compare the air option using actual RAM height and any required front-fan lift. After assembly, test sustained temperatures and adjust fan curves for the real workload.
When to keep what you have
Keep an existing cooler that mounts correctly and meets measured temperature and noise goals. A new cooler style is not automatically an improvement.
Checks still to make
- Exact mounting kit and motherboard pump compatibility.
- Installed air-cooler height or full radiator/fan stack.
- Fan/pump headers, tube routing and access for cleaning.
Check one change with your build
Choose a part to review against your current list. The builder shows any replacement and compatibility checks before you confirm the change.
Sources and scope
The decision examples are RigAtlas analysis based on the specifications below. We have not benchmarked these parts for this comparison. Manufacturer requirements can change; check the exact model before ordering.