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The ARCTIC Freezer 4U-OneX is designed specifically for AmpereOne processors using the LGA5964 socket. Its distinctive copper base covers the direct die and surrounding heat spreader, while included thermal pads address the adjacent interface. ARCTIC specifies a 151 mm installation height and 53 mm RAM clearance; check your chassis and motherboard layout before buying. In ServeTheHome’s April 2026 mini-review, the cooler was judged a little better-performing and quieter than the Dynatron W23, but the article does not provide temperature or noise measurements to quantify that comparison.
Does the Freezer 4U-OneX fit AmpereOne?
Yes. ARCTIC lists the Freezer 4U-OneX (part number ACFRE00193A) for AmpereOne processors and specifies compatibility with the Ampere LGA5964 socket. It is not the same model as ARCTIC’s Freezer 4U-M Ampere, which is intended for the separate LGA4926 Ampere Altra socket. Check the exact cooler model and socket before ordering.
The OneX’s custom copper base is designed to cool both the direct die and the surrounding heat spreader. That contact arrangement is central to its AmpereOne installation: the cooler package includes MX-7 thermal paste and pads for the surrounding interface. See ARCTIC’s Freezer 4U-OneX product page for its compatibility and package details.
Will it fit in a 4U case?
ARCTIC gives the cooler’s dimensions as 124 × 151 × 156 mm and its net weight as 1,479 g. The company lists 53 mm of RAM clearance and an optimized installation height of 151 mm, which it says suits standard 4U server racks and most consumer 4U cases. The 156 mm overall dimension and 151 mm installation-height figure are distinct published measurements, so use the installation-height specification alongside the clearance available in your particular case rather than treating “4U” as a universal fit guarantee.
#1 Best Overall
- ALTRA COMPATIBILITY: This Freezer 4U-M (Rev. 2) does not offer out-of-the-box compatibility with Ampere ALTRA and ALTRA Max, but it can by using the seperate Ampere Kit. Alternatively, a version of the product with an integrated kit is also available
- COMPACT: The Freezer 4U-M (Rev. 2) is your space-saving solution. It won't disrupt your RAM slots and is compatible with dual-CPU motherboards. It's compact design fits seamlessly into 4U server cases and larger, saving you valuable space
- HIGH-PERFORMANCE: Featuring two custom-designed 120 mm fans, the Freezer 4U-M (Rev. 2) ensures outstanding heat dissipation. Fine-tune your performance with PWM control for optimized operation
- DURABLE: Our Freezer 4U-M (Rev. 2) features 120 mm fans equipped with double ball bearings, engineered for continuous operation. They're ultra-durable, making them the ideal choice for 24/7 use
- EASY INSTALLATION: The Freezer 4U-M (Rev. 2) comes complete with thermal paste, pre-installed mounting brackets, and utilizes our exclusive mounting points, making installation a breeze
Before buying, compare the cooler against the chassis manufacturer’s CPU-cooler height limit and check the motherboard layout, memory heat spreaders, nearby components and intended airflow path. A stated RAM clearance does not establish compatibility with every DIMM shape or board arrangement.
What cooling hardware and specifications does it have?
| Item | Published specification |
|---|---|
| Heat sink | Eight 6 mm heat pipes; 57 aluminum fins |
| Fans | Two 120 mm PWM dual-ball-bearing fans |
| Fan speed | 400–3,300 rpm, per ARCTIC |
| Airflow | Up to 81 CFM per fan, per ARCTIC |
| Electrical details | 12 V DC; 0.29 A; 300 mm cable; 4-pin connector |
| Operating ambient temperature | 0–40 °C, per ARCTIC |
These are manufacturer specifications, not independent measurements of cooling or acoustics. The fan-speed range and maximum airflow do not, by themselves, establish CPU temperatures or noise in a particular system. ARCTIC’s specification sheet provides additional published details.
Rank #2
- Ampere Ready: Mounting Kit for Ampere Altra and Altra Max Processors in the Box. Enables top notch cooling performance for the latest ARM-CPU. Fits ASRock Rack ALTRAD8UD-1L2T, ADLINK Ampere Altra Dev Kit COM-HPC module and other Ampere Altra boards.
- Compact: The Freezer 4U-M is your space-saving solution. It won't disrupt your RAM slots and is compatible with dual-CPU motherboards. It's compact design fits seamlessly into 4U server cases and larger, saving you valuable space
- High-Performance: Featuring two custom-designed 120 mm fans, the Freezer 4U-M ensures outstanding heat dissipation. Fine-tune your performance with PWM control for optimized operation
- Durable: Our Freezer 4U-M features 120 mm fans equipped with double ball bearings, engineered for continuous operation. They're ultra-durable, making them the ideal choice for 24/7 use
- Easy Installation: The Freezer 4U-M comes complete with thermal paste, pre-installed mounting brackets, and utilizes our exclusive mounting points, making installation a breeze.
How does installation work, and what should you handle carefully?
The included thermal interface materials and the cooler’s contact with the surrounding AmpereOne area make careful placement important. ARCTIC’s Freezer 4U-OneX manual identifies PH1 and PH2 Phillips screwdrivers and warns that the pads are very soft and may tear when their protective film is removed. It recommends carefully lifting the film with a utility knife. Follow the manual’s diagrams for placement and mounting rather than improvising pad positions.
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- Check the manual’s diagrams and identify the pad locations before removing any protective film.
- Use care when peeling the film from each pad; the manual warns that the soft material can tear and recommends a utility knife to lift the film carefully.
- Use the specified Phillips screwdriver size for the relevant screws and follow the manual’s mounting sequence.
- Orient the fans as shown: the push fan belongs on the heat-sink inlet side and the pull fan on the outlet side.
- Use the manual’s wiring diagram to match the fan connection to the available 6-pin or 4-pin CPU fan-header configuration.
In his review, ServeTheHome’s John Lee describes screwing the retention brackets onto the heatsink, applying thermal interface material to the additional AmpereOne controller chiplets, and setting up the fans in push-pull. He reports that installation was quick and easy in the build shown, which used DDR5 RDIMMs without a fitment issue. That is a report about one setup, not a guarantee for other boards, memory or cases.
Rank #3
- Specially designed air cooler by ARCTIC for the high-performance AmperOne 64-Bit Multi-Core Processors for Socket LGA5964
- COMPACT: With 53 mm of RAM clearance, memory modules with moderate heatsinks can be used without issue. The compact design also fits seamlessly into common 4U server cases and larger
- HIGH-PERFORMANCE: Featuring two custom-designed 120 mm fans, ensuring outstanding heat dissipation. Fine-tune your performance with PWM control for optimized operation
- DURABLE: Our Freezer 4U-OneX features 120 mm fans equipped with double ball bearings, engineered for continuous operation. They're ultra-durable, making them the ideal choice for 24/7 use
- EASY INSTALLATION: The Freezer 4U-OneX comes complete with thermal paste and utilizes mounting points, making installation a breeze
How does it compare with the Dynatron W23?
John Lee’s ServeTheHome mini-review, published April 18, 2026, compares the Freezer 4U-OneX with the Dynatron W23 AmpereOne 3U active cooler previously reviewed. Lee writes that the ARCTIC cooler “performed a bit better and runs quieter,” in the context of a larger 4U cooler with 120 mm fans. This is a qualitative reviewer judgment, not a quantified result.
The inspected review and ARCTIC materials do not provide independent temperature figures, sound-pressure levels or a repeatable test methodology for that comparison. There is therefore no supported temperature difference or noise reduction to report. A meaningful head-to-head assessment would need comparable chassis and hardware, the same workload and ambient conditions, and disclosed temperature and noise measurements.
Rank #4
- COMPATIBLE WITH AMPERE LGA4926: Offers compatibility with Ampere Altra and Altra Max processors and includes a platform‑specific mounting kit for straightforward installation.
- EIGHT 6 mm DIRECT-TOUCH HEATPIPES: Large contact surface with heatpipes ensure efficient heat transfer for workstation processors.
- HIGH PERFORMANCE DUAL FANS SETUP: Leveraging ARCTIC’s P Series strengths and dual ball bearing, they generate high static pressure to ensuring optimal airflow for enhanced cooling.
- ENGINEERED TO REDUCE TOTAL OWNERSHIP COST: Dissipates up to 350W of CPU heat while consuming only 2.88W, significantly reducing energy demands and the Total Cost of Ownership (TCO).
- RAM COMPATIBILITY AND CLEARANCE: The Freezer 4U-Altra offers a generous 53 mm of clearance for memory, allowing the use of RAM modules with moderate heatsinks.
What are the price and warranty?
ARCTIC lists a €79.99 MSRP and a six-year warranty on its product page. MSRP is not a current street price or proof of stock; regional price, availability, shipping and warranty applicability can vary. Confirm the terms and price for your location with ARCTIC or the seller before purchasing.
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Best Value
- CONTACT FRAME FOR INTEL LGA1851 AND LGA1700: Improved contact pressure distribution through Intel mounting frame for efficient heat transfer thanks to even CPU contact surface
- HIGH-PERFORMANCE FOR HIGH-END CPUs: With its 4 offset heat pipes, the single-tower cooler enables fast heat transfer to the heat sink. There, the heat is efficiently dissipated by pressure-optimised 120 mm fans.
- INNOVATIVE FAN MOUNTING: Innovative click installation system makes it easier to install the cooler or replace the fans. The Freezer 36 is compatible with most 120 mm fans
- SIDE-FLOW HEAT SINK: By opening the fins on the side, the pull fan draws additional cool air out of the case through the heat sink, optimises ventilation and increases cooling efficiency
- 6 YEARS WARRANTY: We are convinced of the quality and durability of our products, and we are happy to pass this on to our customers
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
