Dell says customers can't fill racks with Tesla K20 servers

SAN JOSE: TIN BOX FLOGGER Dell said that companies will find it hard to fill full racks of servers with GPGPUs due to power supply limitations.

Dell offers several different Poweredge servers that sport GPGPU accelerators and the firm also offers a library of information to its customers about extracting the best performance and bang for their bucks. It said that most customers will find it hard to fill a 42U rack with its Poweredge C8220X servers that can be equipped with two Nvidia GPGPU accelerators per rack unit due to power supply constraints.

Dell's Poweredge C8220X modular server chassis allows customers to specify whether they want CPU, GPU or storage modules, with the option of having four modules, each of which can house two Tesla K20 GPGPU accelerators, in 4U of rack space. This impressive engineering feat is however negated by its claim that most 42U racks would not be able to supply enough power to house that many accelerators.

Dell has also done research to look at how to lower the power consumption of Nvidia's GPGPU accelerators and what effect capping the power consumption to lower than the default 225W has on overall system performance. It found that capping the GPGPU power at 200W gave a four percent increase in performance per Watt and that in general overclocking the GPGPU did not improve performance per Watt.

Dell also said that tweaking the power consumption of Nvidia's Tesla K20 should be the first priority for firms looking to reduce overall system power consumption. The firm said that while tweaking CPU settings in the BIOS and through its software would also help, tinkering with the Tesla K20 settings should be the "first order priority".

Although Dell admitted that Nvidia's Tesla K20 GPGPU accelerators provide major performance per Watt improvements over CPUs, it is clear that customers will need to look at raw power consumption and how they plan to deliver that much power before buying a rack of fully populated GPGPU servers. Dell's research also suggests that customers should tweak the power consumption of Nvidia's Tesla K20 boards if they want to achieve optimal performance per Watt. µ