ARCTIC Liquid Freezer III Pro 420 - AIO CPU Cooler, 3 x 140 mm Water Cooling, 38 mm Radiator, PWM Pump, VRM Fan, AMD AM5/AM4, Intel LGA1851/1770 Contact Frame - Black
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AI Verdict
This 420mm AIO with a 38mm radiator and P14 Pro fans is for serious builders needing top-tier cooling for high-TDP CPUs on AM5/AM4 or LGA1851/1700.
This cooler is a strong fit for high-performance desktop systems needing maximum thermal dissipation, thanks to its 420mm, 38mm thick radiator and dedicated VRM cooling. It's built for the latest power-hungry CPUs on AM5/AM4 and LGA1851/1700 sockets.
If you need this level of cooling but have a smaller case, look for a 360mm version of this cooler, ensuring it still features the P14 Pro fans and VRM cooling.
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Pros
- The 38mm thick radiator with an extended fin stack increases cooling surface by 23%, improving heat dissipation and liquid volume.
- ARCTIC's P14 Pro fans offer a higher maximum speed (2500 rpm) and static pressure (5.2 mmH2O) for optimal cooling under heavy loads.
- The integrated VRM fan, PWM-controlled up to 2500 rpm, actively cools voltage regulators, ensuring stable performance for overclocking or power-hungry CPUs.
- Native offset mounting shifts the cold plate to the CPU hotspot, enhancing heat transfer efficiency for Intel and AMD processors.
- The included Intel LGA1851/1700 contact frame optimizes contact pressure, potentially extending CPU life and improving heat dissipation.
- Integrated cable management routes fan cables through the hose sheathing, simplifying installation and reducing visible clutter.
Cons
- The 420mm radiator and pump block require significant case clearance, with users reporting tight fits in some full towers.
- Some motherboards with oversized M.2 SSD coolers in the M.2_1 slot may interfere with the pump block, though Arctic offers a free compatible cooler.
- The integrated VRM fan cannot be completely stopped, even with a 0% PWM signal, potentially contributing to constant low-level noise.
- The fixed position radiator fittings mean no rotation, which can limit tube routing options in some builds.
Dimension Scores
The 38mm radiator with a 23% extended fin stack and 3x P14 Pro fans (110 cfm, 5.2 mmH2O static pressure) provides exceptional heat dissipation.
Users report 'great thermal performance with fans running at maximum RPM and in the important 40 decibels noise test this tops our charts,' but the VRM fan cannot be stopped.
Features like a copper cold plate, aluminum radiator, and a 6-year warranty indicate a focus on durability and longevity.
Integrated cable management routes fan cables through the hose sheathing, resulting in only one visible cable connection to the motherboard.
Best For
- Cooling high-end AMD AM5/AM4 or Intel LGA1851/1700 CPUs, especially those with high core counts or overclocked.
- PC builds in large cases designed for 420mm radiators, where maximum thermal performance is the priority.
- Users who want optimized CPU contact and VRM cooling for system stability under sustained heavy loads.
Not Recommended For
- Compact PC builds or cases with limited radiator clearance (less than 63mm).
- Users who prioritize absolute silence at all times, due to the non-stoppable VRM fan.
Watch Out For
- Case compatibility is a major hurdle; the 458mm (L) x 138mm (W) x 38mm (H) radiator and pump block are 'super big' and may not fit without careful planning.
- Motherboard M.2_1 slot interference can occur with oversized SSD heatsinks, requiring a free replacement cooler from Arctic or alternative mounting.
- The VRM fan runs continuously, even at 0% PWM signal, meaning it will always contribute some noise to the system.
Full Specifications
| UPC | 840033403016 |
| ASIN | B0DPHQ1353 |
| Brand | ARCTIC |
| Voltage | 12 Volts |
| Wattage | 4.2 watts |
| Material | Metal, Plastic, Rubber |
| Item Weight | 5.22 pounds |
| Manufacturer | ARCTIC |
| Cooling Method | Liquid |
| Number of Items | 1 |
| Air Flow Capacity | 110 Cubic Feet Per Minute |
| Item model number | LFIII Pro 420 |
| Compatible Devices | Desktop |
| Product Dimensions | 18.03 x 5.51 x 2.66 inches |
| Power Connector Type | 4-Pin |
| Maximum Rotational Speed | 2500 RPM |
| Global Trade Identification Number | 04895265000348 |
What Buyers Say
The biggest takeaway from users is that this 420mm AIO is a performance beast, often cited as one of the best coolers available for high-end CPUs, especially considering its price point. However, its sheer size is a recurring theme, with many emphasizing the critical need to verify case compatibility before buying. The integrated VRM fan is a unique feature that users appreciate for motherboard component cooling, though its inability to fully stop is a minor point of contention.
“Man, this thing cools my 7950X3D like it's nothing, but seriously, measure your case twice, I barely squeezed it in my Lian Li O11 EVO.”
Common Praise
- Provides 'really really well' cooling performance for high-TDP CPUs like the 9950X3D.
- Considered 'the best cooler on the market right now for a reasonable price.'
- The 38mm thick radiator and P14 Pro fans deliver 'great thermal performance.'
- Installation is 'easy' and 'straightforward' due to pre-installed fans and integrated cabling.
- The integrated VRM fan effectively lowers voltage regulator temperatures, ensuring stable performance.
Common Complaints
- The cooler is 'super big' and requires significant case clearance, leading to tight fits in many cases.
- Motherboard M.2 SSD heatsinks can interfere with the pump block on some models, requiring workarounds.
- The VRM fan cannot be turned off completely, even at a 0% PWM signal.
Ownership Tips
- The included MX-6 thermal paste is decent, but some users opt for thermal pads or other high-performance pastes for marginal gains.
- The single-cable control option simplifies motherboard connections, but the splitter cable offers more granular control over pump, VRM, and radiator fan speeds.
- The 6-year warranty provides peace of mind, which is a plus for a component that's critical for CPU longevity.
Frequently Asked Questions
What CPU sockets is this cooler compatible with?
It's compatible with Intel LGA1851 and LGA1700 sockets, as well as AMD AM5 and AM4 sockets.
Does it come with thermal paste?
Yes, the cooler includes ARCTIC MX-6 thermal paste for installation.
How are the fans controlled?
You can control the pump, VRM fan, and radiator fans independently using a splitter cable, or all together via a single PWM signal with the all-in-one cable.
Is the VRM fan always on?
Yes, the integrated VRM fan cannot be completely stopped, even when a 0% PWM signal is sent to it.
Will this fit in my case?
This is a very large 420mm AIO. You need to check your case specifications for at least 63mm of clearance for the radiator and fans.
Buying Guide
When you're looking at liquid coolers like this, you're basically trying to move heat away from your CPU as efficiently as possible. A bigger radiator, like this 420mm one, means more surface area to dissipate heat. The fans push air through that radiator, and the pump circulates the liquid. The VRM fan is a bonus, cooling the power delivery components on your motherboard that can get hot with powerful CPUs, which helps keep your system stable.
420mm Radiator
This is the size of the heat exchanger. Think of it like a bigger car radiator – more surface area means it can shed more heat, which is crucial for keeping powerful CPUs cool under heavy loads.
38mm Radiator Thickness
A thicker radiator holds more coolant and has more fin surface area inside. It's like having a deeper pool of water to cool down; it can absorb and release more heat before getting saturated.
P14 Pro Fans
These fans are designed for static pressure, meaning they're good at pushing air through restrictive environments like a radiator. Higher static pressure (5.2 mmH2O) and airflow (110 cfm) means more air moves through the radiator, taking more heat with it.
Integrated VRM Fan
This small fan cools the Voltage Regulator Modules on your motherboard. These components get very hot, especially with high-end CPUs or overclocking. Keeping them cool prevents throttling and ensures your CPU gets stable power.
Alternatives
If this cooler is too large for your case, search for 360mm AIOs with a 38mm or thicker radiator and high static pressure fans. If you don't need the VRM cooling, you might find slightly more compact options.
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