Deepcool AK400, cooler with unconventional contact plate
Deepcool has released a cooler that is closer to AMD’s chiplet processors than competing models with DHT bases. The outermost heatpipes are spaced farther apart from the ones in the middle. It could be designed so that they pass over the processor cores, i.e. on the outer edges of the chiplets. This would allow for faster heat transfer, but this is just one of many premises for top efficiency. However, the Deepcool AK400 also performs well as a whole.
The new Deepcool AK400 cooler is derived from the larger AK620. The main difference is that the AK400 is smaller and does not consist of two towers with stacked fins, but only one. There is also “only” a single fan and the total weight is less than half (661 g). At first glance, the AK400 looks like a chopped off half (one tower with fan) of the AK620 cooler. In addition to the same top fin cover, it also uses the same 120 mm fan, and the heatsink fins differ only in that they don’t have a cutout on the bottom for better compatibility with memory modules. In this case, there’s no need for that, as the heatsink is slim enough not to cross the axis of the DIMM memory slots.
The design of the heatsink alternates between two shapes of aluminium fins. One shape has protrusions where the other is cut to create a matrix pattern in the final side. However, Deepcool does not state what the significance of this modification is and whether it is used to improve functional properties or just for effect.
The fan is characterized by an axial rotor with long blades with a large difference in width between the beginning (at the motor housing) and the end (at the frame). Anyway, the blade area is large and if this fan goes on sale itself, we will definitely give it a run for its money in our tests. For now, however, it is available exclusively as part of CPU coolers. The stated maximum airflow (at 1850 rpm) is 113 m3/hr and a static pressure of 2.04 mm water column. Whether these are the correct parameters is difficult to estimate. For the AK420 with the same fan, different, higher values are given.
One of the most notable things is the contact area of the base, which we mentioned at the beginning of the article. The AK400 has a “DHT” type of base (i.e. with direct pipe contact with the processor’s heat spreader). This is also the biggest design difference from the AK620 after removing one cooling tower – this cooler has heatpipes soldered to a copper block. Omitting it is a manufacturing cost saving (no improvement for better contact without two interleaved layers as the marketing materials try to sell it, don’t get fooled by that), but the arrangement of the heatpipes here is remarkable.
The two pipes in the middle are contact-pressed on each other without any gap. The other two, the outermost, already have some spacing. But that’s apparently to run through the space above the cores of AMD Ryzen processors. These are divided between two chiplets. The cores in the I/O chiplet axis are still under the two “inner” heatpipes and the remaining ones (on the outer sides with respect to the PCB) are already under the outer heatpipes. I mean, hopefully, because we find no other justification in this heatpipe layout. If the four heatpipes were packed tightly, as some coolers have them, they would no longer reach some of the Ryzen processor cores. With the typical spacing between all the pipes, there is locally higher CPU temperature, especially in the case of Intel processors with centered chips. Thus, the AK400 pipe layout is quite universal and the deterioration of the heat conducting properties should not be a problem for Intel processors either. At 11.7 mm in width, the Alder Lake generation silicon chip is still narrower than two heatpipes pushed together at 6 mm across each.
The claimed TDP of the cooler is 220 W and in addition to the LGA 1700 platform, it also supports LGA 1200/1150/1151/1155 and AMD AM4. Deepcool AK400 is already on sale and its recommended price is 35 EUR. In June this year, a completely white (including the heatpipe surface) variant of the AK400 should be added to the offer.
English translation and edit by Jozef Dudáš