Lenovo has introduced a new high-density server \u201ctray\u201d for high-performance computing (HPC) environments with the newest generation of water cooling technology it co-developed with a German HPC firm.\nUnlike your typical water-cooled system, where the water is chilled almost to a drinkable state, the ThinkSystem SD650 high-density server tray \u2014 so called because of its design and shape \u2014 is designed to operate using warm water, up to 50\u00b0C, or 122\u00b0F.\n\nThere is a mindset that CPUs have to be chilled as though they were cold cuts, when Intel says they can handle much higher temperatures. Xeons can handle temps of up to 75\u00b0C without becoming unstable or crashing.\nBy using warmer water, Lenovo claims it will lower power consumption 30 to 40 percent compared to traditional air cooling methods.\nWater cooling costs less and is more effective\nNot only is it a cheaper method of cooling, but it\u2019s more effective. Air cooling is only effective up to about 10 kilowatts of power in a server chassis, while water cooling can handle 70 kW or more.\nAnd the ThinkSystem SD650 is one seriously dense server tray.\u00a0 Each tray has two sockets, and up to 12 trays can be squeezed into one 6U NeXtScale n1200 enclosure. That translates to 24 Xeons, 9.2TB of memory, 24 SFF SSDs or 12 SFF NVMe drives, and 24 M.2 boot drives.\nLenovo developed the cooling system with the Leibniz Supercomputing Center (LRZ) in Germany. Later this year, the center will deploy a 100 rack supercomputer consisting of 6,500 ThinkSystems SD650s with 26.7 petaflops of peak performance. That would make it the number three supercomputer on the Top500 supercomputer list as of November 2017, but there will undoubtedly be other contenders.\nThe direct-water cooled design allows for up to 90 percent heat recovery, meaning only 10 percent of the heat generated by the CPU has to be addressed with an air conditioner or fan. In fact, the SD650 doesn\u2019t come with a fan, except for its power supply. This translates to a much quieter data center.\nWater cooling is growing in popularity mostly out of necessity because air cooling is simply not sufficient for an ultra-dense server environment. The initial acquisition costs are a little higher, but they pay off over time with reduced ongoing costs.