DeepCool AK620 and AK400 G2 Review: Quiet and powerful, with woodgrain or a digital display

DeepCool has been delivering innovative, interesting, and often budget-conscious PC cases and cooling products for more than a decade. Its current lineup includes air and AIO coolers, computer cases, keyboards, power supplies, and other accessories.

We were impressed by the company’s AK620 and Assassin VC Elite air coolers in the past. In 2024, the Beijing-based company was banned from selling products in the U.S., but has continued to produce and improve its cooling products for markets elsewhere. US consumers also have the option of importing the cooler, if you don’t mind paying for extra shipping costs.

Here, we’re looking at DeepCool’s second-generation AK series coolers, the AK400 G2 and AK620 G2. These are available in two styles: one with woodgrain top covers, the other featuring a digital display.

Let's take a look at the specifications and features of the coolers, then we’ll go over thermal and noise benchmarks and decide if DeepCool’s AK G2 series coolers deserve to make our list of the best CPU coolers.

DeepCool AK620 G2/AK400 G2 specifications

Features of DeepCool’s AK G2 Air coolers

▶️ Heatpipes and heatsink

With the single-tower AK400 G2, four slightly staggered direct-touch copper heatpipes are embedded in the base to transfer heat from the CPU into the heatsink and its fins.

The larger, dual-tower AK620 G2 features six evenly spaced copper heatpipes.

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The heatsink fin designs are similar in both models. The front ends feature a jigsaw-type design, shown below.

The exhaust side features the checkerboard matrix style DeepCool’s air coolers are known for, a design choice which the company says improves static pressure.

▶️ High-performance 120 mm fans

There’s more to a cooler than just the heatsink. The included fans directly impact noise levels and cooling performance. The fans included on both AK400 and AK620 G2 models are essentially the same – but the AK400’s single fan runs up to 10% faster than the two fans included with the AK620 G2.

▶️ Woodgrain and digital display styles available

Both the AK400 and AK620 are available in black or white, but there are two sub-choices for the aesthetic. The versions we’ve tested for this review feature woodgrain, a motif that’s been increasing in popularity in DIY PCs since the release of Fractal’s North computer case.

If you don’t like woodgrain, DeepCool also includes a checkerboard black cover that you can use in place of the woodgrain covers.

There’s also the Nyx version of the AK620 G2 available, which features a digital display showing CPU performance metrics – temperature, frequency, power consumption, and overall CPU usage.

▶️ RAM Clearance

The AK400 G2's design is such that it doesn’t overhang or interfere with the DIMM slots, ensuring that all sizes of RAM, no matter how tall, are compatible.

Standard-height DDR5 sticks 40mm tall fit well under the larger AK620 G2, but taller sticks won’t fit perfectly underneath. Our current CPU cooler test bench incorporates TeamGroup’s Sakura Rose T-Force Xtreem DDR5-7200 sticks, which are 48.8mm (1.92 inches) tall.

If you also use taller RAM DIMMs, you’ll have to raise the intake fan’s placement by a few millimeters for things to fit properly, as we did (see image, above). This might result in slightly lower cooling performance in certain scenarios. But even so, the AK620 G2 performed excellently, as you’ll see in the benchmarks section.

▶️ Packaging

The outer packaging is typical of DeepCool products: a basic brown box with a blue line and DeepCool’s logo, covered by a wraparound showing a picture of the cooler.

The heatsink and fans are protected by molded foam, and the accessories are contained in a small cardboard box. Included with the package are:

Mounting hardware for AMD and Intel platforms
Alternative top covers
Screwdriver (AK620 G2 only)
The AK620 G2 includes a tube of thermal paste; the AK400 G2 includes pre-installed thermal paste
Single-tower (AK400 G2) or dual-tower (AK620 G2) heatsink
120 mm fans and fan clips
Installation manual

▶️ AK620 G2 AM5 Installation

You’ll need to first remove the default AM4/5 retention mechanism and then place the mounting studs around the exposed screw holes.

The next step is to place the mounting bars on top of the studs, securing them with the included screws, and then apply the included thermal paste. If you’re not sure how to do that, we have a handy thermal paste application guide that covers the different methods you can use. Afterwards, place the heatsink tower against the CPU and mounting bars, and use a screwdriver to secure it.

Once the heatsink is secured, attach the 120 mm fans to the heatsinks. Lastly, connect the PWM cables of the fans to the corresponding headers of your motherboard.

Real-world testing configuration – AMD AM5 platform

We’ve tested coolers with both the Ryzen 9950X3D and its non-V-Cache sibling, the 9950X. There are some differences in how the 9950X and 9950X3D CPUs are impacted by thermal events. While the heat output of the CCDs of AMD’s 9950X3D is relatively balanced, the 9950X has one CCD that runs much hotter than the other, with a difference of over 10 degrees Celsius in some scenarios, shown below.

The benchmark results shared in these reviews may differ from others because I emphasize results that are comparable to real-world use. This means I generally test CPU coolers inside of a closed desktop case, which increases cooling difficulty compared to other testing methods.

Many reviewers test coolers on an open test bench, which has lesser airflow needs and lowered ambient temperatures. This results in weak coolers appearing stronger than they really are. Some have also used generic thermal plates to test cooling solutions. I feel that these methods don’t accurately reflect real-world cooler conditions.

Our latest testing setup uses the Flova F50 computer case from Tryx.

This case features a unique “crossflow” fan that pulls air from the side, which the company claims is more effective than traditional intake fans. For air cooling tests, we’ve added a single Noctua NF-A12 G2 intake fan.