At Computex 2019, Gigabyte showed off water-cooled versions of servers. The servers were cooled by Asetek systems. For STH readers an interesting factoid is that the NVIDIA Tesla P100/ Tesla V100 platform and AMD EPYC 2U4N platforms are both ones that STH has reviewed in the last few quarters.
Gigabyte G481-S80 Water Cooled
As an 8x GPU server, the Gigabyte G481-S80 can put off a lot of heat. Indeed, in our Gigabyte G481-S80 review, we called this 8x NVIDIA Tesla GPU server the DGX1.5 since it takes eight SXM2 NVIDIA Tesla GPUs along with newer Intel Xeon Scalable technology.
In the demo, there are eight water blocks, one for each NVIDIA Tesla GPU. Power cables were not connected so we think this was more of a showcase capability demo. We did not see the CPUs being liquid cooled in this chassis. Here is a photo from our review of the enormous air coolers that cover the GPUs without this Asetek solution.
In our review, we noted the rear ports for liquid cooling. One can see four sets of hot/ cold connections in the back of the chassis.
These tubes are then fed to an external distribution system and one can see the cooling unit below the G481-S80.
Gigabyte H261-Z60 Water Cooled
You can read the STH review of this server (on air cooling) here: Gigabyte H261-Z60 Server Review 2U4N AMD EPYC for Dense Compute. The Gigabyte H261-Z60 is a 2U 4-node (or 2U4N) server which means it puts up to eight CPUs in a 2U chassis. Beyond that, these CPUs can reach 200W or more.
One can see that the Asetek solution here is cooling the CPUs. Liquid cooling is not extended to the memory or add-in cards in this display which means the platform still needs airflow to operate.
As CPUs and GPUs get hotter, and manufacturers attempt to maintain density, liquid cooling is an important technique that companies can use. In our testing, we found both of these systems can use around 1kW per U of rack space which means significant heat needs to be removed from the chassis. Liquid cooling adds complexity, but it can also be more efficient as densities rise to 1kW per U and above.