Deepcool Assassin III Review and Test in 2021

  • Cooling performance – 10/10
  • Volume – 8/10
  • Installation – 10/10
  • Price-performance – 9/10
  • Processing – 10/10

9.4 / 10

The Deepcool Assassin III was designed to compete with the king of air coolers – the Noctua NH-D15. And boy, Deepcool has succeeded. In our tests, the cooling performance is better than that of the Noctua, especially in OC scenarios. Unfortunately, we have to subtract a bit in terms of volume since the Assassin III does get louder under load. 

The ultra-light and quick installation make up for that. Currently, for the same price as the uglier brown Noctua cooler and even 10 € cheaper than the black version of it, there is little to complain about. We were also completely enthusiastic about the processing. Absolute buy recommendation from us!

Deepcool Assassin III

Features & Packaging

The Deepcool Assassin III is a twin tower cooler with seven heat pipes with a diameter of 6 mm, which come along as a sintered and grooved construction and protrude from the copper base. There are forty-four aluminum cooling fins per tower and two black 140 mm PWM high-performance fans with fluid dynamic ball bearings.

deepcool assassin 3

In the following we have summarized the most important key data of the Deepcool Assassin 3 for you:

  • Socket: Intel LGA2066 / 2011-v3 / 2011 / 115x / 1366, AMD AM4 / AM3 + / AM3 / AM2 / FM2 + / FM2 / FM1
  • Dimensions: 161x140x165 mm
  • Weight: 1464g
  • Heat pipe: ø6mm x7pcs
  • Fan dimensions: 140x140x25 mm
  • Fan speed: 400 – 1400RPM
  • Airflow: 90.37 CFM
  • Pressure: 1.79 MMA
  • Volume: 29 – 45 dbA
  • Fan connection: 4-pin PWM
  • Ball-bearing type: fluid-based dynamic bearing
  • Power consumption fan: 2.52W

Deepcool rated the Assassin III up to 280W TDP. The cooler is 165 mm high (depending on the fan position), 140 mm long, and 161 mm wide when both fans are installed. The socket compatibility covers all common and current Intel and AMD variants.

The cooler is well packed, padded, and safely stowed in the box. Also, everything is clearly labeled, and an accessory box is included in the scope of delivery. This contains:

  • 2x premium fans
  • Low noise adapters
  • Fan clips
  • Cleaning cloth
  • High-quality thermal paste
  • Mounting kit
  • screwdriver

deepcool assassin

Design & Processing

With its simple, elegant design, high-gloss polished cooling fins, and cool black fans, the Assassin III definitely overtakes the NH-D15 because not everyone likes the brown from Noctua (although Noctua has now released a black version – but this is around 10 € more expensive).

The cooler itself is very well made, the nickel coating of the heat pipes is smooth and even – this also applies to the base plate.

deepcool assassin

The heat transfer plate’s top employs a fin design for heat dissipation that is not too dissimilar to a water cooling block. This shape should possibly help to dissipate heat a little faster.

The fan can be used in PWM mode, which is controlled from your mainboard. Overall, you should easily install the cooler without blocking any parts connected to the motherboard, including most RAM modules.

deepcool assassin

Deepcool Assassin III Vs Noctua NH-D15

Since we like to compare the Assassin III with the Noctua NH-D15 and want to compete directly with it, we like to compare the two again and again in this article. Compared to the NH-D15, the dimensions are very similar.

The two’s height and depth are almost identical at 165 x 161 mm, but the NH-D15 is slightly wider at 150 mm, while the Assassin III is only 140 mm, which creates a little more space between the cooler and the first PCIe slot.

The Assassin III has a total of seven heat pipes, with the NH-D15 only having six, while the NH-D15 with forty-five has a slightly higher number of fins than the Assassin III with forty-four. Technically, the NH-D15 has a little more cooling surface.

In terms of weight, the Assassin III is the heavier of the two at 1464g, with both having 140mm fans built-in. The NH-D15 weighs 1320 g with the fans installed, which is a considerable saving in weight and should put less strain on the motherboard/fasteners.

Aside from the differences noted above and the NH-D15’s larger 150mm fans, the design and appearance are very similar. We personally like the look of the black fans on the Assassin III, as they match most colors better than the standard brown fans on the NH-D15.

Installation and Assembly

The mounting kit for installation in four steps simplifies the installation of such a large air cooler.

Overall, the installation process is very simple and straightforward. The assembly of the cooler is easy. The assembly kit is robust, handy, and very easy to install. Your mainboard probably has to get out of the case. Otherwise, it will be very tricky.

However, it should be noted that by increasing the fan height (space for RAM), the total height of the cooler is up to 195mm, which can cause problems in tight cases. Therefore, please pay attention to it and measure again in your housing.

deepcool assassin

When the fans are in the standard position, the maximum RAM clearance is 31 mm. To keep the cooler’s maximum height, including fans at 165mm, we recommend moving the front fan in the pull configuration to the I / O side of the cooler to free up more space for the RAM and improve case compatibility.

After inserting it, you can now connect the fan power cable either to the CPU-FAN header on the motherboard or to a FAN controller. The installation takes a maximum of 10-15 minutes, and then we were already for our stress test.

Performance Tests

The temperatures were tested on a current Z390 mainboard with an i7-9700K CPU. We tested three things:

  1. The volume of the cooler
  2. CPU temperature in idle with the basic clock
  3. CPU temperature under load (OC)

Note that all of our tests are performed at a room temperature of approximately 23 degrees.

First, the cooler was measured in Windows idle for 20 minutes, the i7-9700K runs at 3.6 GHz.

The 9700K was first increased to 4.7 GHz and then 5.0 GHz on all cores to simulate an overclocked frequency. The temperatures measured are delta average temperatures measured over the length of the test. We calculate the delta temperature by subtracting the test room’s ambient temperature from the measured CPU temperature both during idle and under load.


All idle temperatures are measured by leaving the system idle in Windows for 20 minutes. The load temperatures are reached when the AIDA64 again claims the CPU, FPU, and cache for 20 minutes. This should give the CPU enough time to reach its maximum temperature.

During the test, all CPU fans are set to maximum speed. The tests were carried out in closed housing to simulate real values.

We did not include the idle temperatures in this diagram. As they were in the range of 5-10 ° C. As you can see, the Deepcool Assassin 3 is completely convincing under load. Even with overclocking to 5.0 GHz and additional load on the graphics card, it remains below 70 ° C. Our tests on the competitor NH-D15 showed higher values, albeit only deviations of 2-3 ° C under maximum load.


The noise level is measured with our sound meter at a distance of 1 meter from the test system. The fans of the cooler are set to their maximum speed. The room’s ambient noise level was measured at 35.0 dB (A), and the cooler’s peak noise level is recorded in dB (A).

You can hardly hear the fans on either cooler while idling. As soon as we have used the processor to 100%, the dbA value increases to around 47 dbA, which is around 3 dbA louder than with the NH-D15.

As a comparison for you: A classroom or office has an average noise level of 50 dbA (moderate). The inside of a car is 70 dbA and is called loud. Therefore, the Assassin 3 with its 47 dbA is still in the frame but is definitely audible.

deepcool assassin

  • Excellent cooling performance
  • Excellent artistry
  • easy installation
  • Many extras included
  • Expensive
  • Very difficult
  • Problematic height
  • Not the quietest under load