The DeepCool AK620 Digital CPU Cooler Review: Big, Heavy, and Lit

Although the testing of a cooler appears to be a simple task, that could not be much further from the truth. Proper thermal testing cannot be performed with a cooler mounted on a single chip, for multiple reasons. Some of these reasons include the instability of the thermal load and the inability to fully control and or monitor it, as well as the inaccuracy of the chip-integrated sensors. It is also impossible to compare results taken on different chips, let alone entirely different systems, which is a great problem when testing computer coolers, as the hardware changes every several months. Finally, testing a cooler on a typical system prevents the tester from assessing the most vital characteristic of a cooler, its absolute thermal resistance.

The absolute thermal resistance defines the absolute performance of a heatsink by indicating the temperature rise per unit of power, in our case in degrees Celsius per Watt (°C/W). In layman’s terms, if the thermal resistance of a heatsink is known, the user can assess the highest possible temperature rise of a chip over ambient by simply multiplying the maximum thermal design power (TDP) rating of the chip with it. Extracting the absolute thermal resistance of a cooler however is no simple task, as the load has to be perfectly even, steady and variable, as the thermal resistance also varies depending on the magnitude of the thermal load. Therefore, even if it would be possible to assess the thermal resistance of a cooler while it is mounted on a working chip, it would not suffice, as a large change of the thermal load can yield much different results.

Appropriate thermal testing requires the creation of a proper testing station and the use of laboratory-grade equipment. Therefore, we created a thermal testing platform with a fully controllable thermal energy source that may be used to test any kind of cooler, regardless of its design and or compatibility. The thermal cartridge inside the core of our testing station can have its power adjusted between 60 W and 340 W, in 2 W increments (and it never throttles). Furthermore, monitoring and logging of the testing process via software minimizes the possibility of human errors during testing. A multifunction data acquisition module (DAQ) is responsible for the automatic or the manual control of the testing equipment, the acquisition of the ambient and the in-core temperatures via PT100 sensors, the logging of the test results and the mathematical extraction of performance figures.

Finally, as noise measurements are a bit tricky, their measurement is being performed manually. Fans can have significant variations in speed from their rated values, thus their actual speed during the thermal testing is being recorded via a laser tachometer. The fans (and pumps, when applicable) are being powered via an adjustable, fanless desktop DC power supply and noise measurements are being taken 1 meter away from the cooler, in a straight line ahead from its fan engine. At this point we should also note that the Decibel scale is logarithmic, which means that roughly every 3 dB(A) the sound pressure doubles. Therefore, the difference of sound pressure between 30 dB(A) and 60 dB(A) is not “twice as much” but nearly a thousand times greater. The table below should help you cross-reference our test results with real-life situations.

The noise floor of our recording equipment is 30.2-30.4 dB(A), which represents a medium-sized room without any active noise sources. All of our acoustic testing takes place during night hours, minimizing the possibility of external disruptions.

*noise levels above this are not suggested for daily use

To begin with, we are having a look at the DeepCool AK620 Digital with its two FK120 fans running at their maximum speed. We measured the top speed of the fans while attached to the heatsink at 1920 RPM, measurably higher than their 1850 RPM unobstructed maximum speed.

Going by both thermal resistance and delta temperatures, the DeepCool AK620 Digital CPU Cooler is on par with the best in the game when it comes to cooling, but it’s a bit louder than average. It hits an impressive 0.0896 °C/W thermal resistance at a max fan speed of 1920 RPM, making it clear it’s built for heavy-duty use. Though it seems to be in the same league as other high-end coolers, the catch is its fans are faster.

When it comes to noise, the AK620 Digital isn’t exactly whisper-quiet, clocking in at 39.7 dB(A) at full throttle. Despite the noise, it’s still a solid choice for those prioritizing cooling performance, showing DeepCool’s attempt to balance brute cooling force with noise control, even if it leans a bit more towards the loud side.

In this test we are switching things up a bit, taking a look at the cooler’s performance with the FK120  fans taken down to half speed.

When the fan speed of the DeepCool AK620 Digital CPU Cooler is adjusted down to 1000 RPM, there is expectedly a noticeable impact on its cooling capability, though a smaller one than what we initially expected from a cooler with low pressure fans. The thermal resistance at this lower speed registers at 0.1177 °C/W, which, despite the decrease, still places the cooler among the best in terms of thermal efficiency within its category. This level of performance under reduced fan speed suggests that the huge mass of the cooler itself, as well as the great heat exchange area, allow it to maintain great figures even when the airflow is limited.

However, even though the speed of the fans has been halved, the noise level of 34.6 dB(A) is somewhat louder compared to some competitors. Despite this increase, the noise produced at this speed is still within a comfortable listening range for everyday use, indicating a well-thought-out balance between noise and performance. This suggests that while the AK620 Digital might produce more sound pressure than some of its quieter rivals, it is not so much as to be a problem.

During our thermal resistance vs. sound pressure level test, we maintain a steady 100W thermal load and assess the overall performance of the coolers by taking multiple temperature and sound pressure level readings within the operating range of the stock cooling fans. The result is a graph that depicts the absolute thermal resistance of the cooler in comparison to the noise generated. For both the sound pressure level and absolute thermal resistance readings, lower figures are better.

This chart reveals where the DeepCool AK620 Digital falls compared to similar designs. Despite its exceptional thermal performance, the AK620 lands right amongst the rest of the similarly sized coolers due to its higher noise levels. Generally, it matches the performance of the best air coolers when the fan speed is high but falls behind when the fan speed is low, not really because its thermal resistance is high but because the noise is, which pushes the chart line upwards.  These results suggest that the AK620 Digital can perform exceptionally if required but cannot reach the dead-silent noise figures that other offerings can.  

DeepCool is making waves in the PC cooling market, and the AK620 Digital CPU Cooler is a prime example of their dedication to pushing the envelope. With its dual tower design, six copper heatpipes, and striking all-black look, this cooler doesn’t just aim for peak performance – it is a product designed to make a statement in high-end PC system. At nearly 1.5 kilograms, it is a literal heavyweight contender that promises to keep even the most demanding systems cool, all while doubling as an aesthetic centerpiece. The $80 price tag is seemingly high for a CPU cooler but, considering the performance on offer and the distinct addition of an LCD display – which is not something you see on your average cooler – the pricing is reasonably competitive.

As far as cooling performance is concerned, the AK620 Digital stands shoulder to shoulder with the best thanks to its excellent thermal resistance and ability to perform under pressure. Even when the fans dial back to half speed, it manages to maintain commendable cooling efficiency, demonstrating that DeepCool has struck a good balance between power and noise. Overall, DeepCool has tuned this design to run a bit louder than many coolers in order to achieve better cooling performance, and while that makes the cooler a poor candidate for builders specifically after whisper-quiet operation, the noise levels are still within a reasonable range overall, making it a solid choice for users who value cooling efficiency first and foremost..

DeepCool’s meticulous attention to design details, from the dense fin arrays to the premium FK120 fans, shows their commitment to quality and user satisfaction. Adjustable fan heights for RAM compatibility and a scratch-resistant copper base plate are thoughtful touches that highlight the cooler’s blend of performance and practicality.

However, what truly sets the AK620 Digital apart is its LCD display, a feature that not only adds to its visual appeal but also offers real-time system monitoring – a luxury at this price point. This inclusion, alongside its robust cooling capabilities, helps the cooler stand out in a crowded market.

To sum up, DeepCool’s AK620 Digital CPU Cooler is an impressive piece of hardware that combines style, functionality, and innovation. The company has clearly put a lot of thought into this cooler, ensuring it meets the needs of demanding users without breaking the bank. Its competitive pricing, exceptional performance, and unique LCD display position it as a top choice for builders and enthusiasts alike that want to own something a little outside the ordinary.