Filling HDDs with helium has multiple benefits, the gas' density is only one-seventh that of air, which results in significantly less drag force acting on the spinning discs, and it also reduces fluid flow forces buffeting the disks and the arms, enabling platters to be placed closer together. These disks promise lower power consumption, lower heat output and may offer capacities of up to 7TB if WD uses 1TB platters.
“We are currently sampling these products with selected customers right now. […] We continue to expect that we will have units shipped and revenue realized before the end of the calendar year. The first generation product will not be a particularly significant volume product to start out with as customers test it out and that sort of thing. So I would doubt whether or not that will meaningfully move the needle in terms of any market share in the capacity enterprise, at least initially. Then we will have to see how the adoption goes from there,” said Stephen D. Milligan, chief executive officer of Western Digital, during the latest conference call with financial analysts.Source: X-bit Labs
The helium-filled hard disk drives can incorporate up to seven platters inside typical 3.5" form-factor, which eliminates need for a breakthrough in areal density to create higher-capacity hard drives. Helium-filled HDDs will not only increase capacities of hard drives and decrease per-gigabyte costs, but may significantly improve datacenter TCO on virtually every level: capacity, power, cooling and storage density as they directly affect such measures as cost-per-terabyte, watt-per-TB, TB-per-system weight and TB-per-square foot.