U.S. hard drive maker Western Digital has announced hard drives filled with helium to improve performance that are cooler, lighter and less power-hungry. The Irvine, Calif., company says the Ultrastar He6 drive from its HGST subsidiary, with a 6-terabyte capacity, is the highest-capacity 3.5-inch hard drive available. Filling them with helium, with only 14 percent the density of air, provides a much lower level of friction for the spinning platters inside the drive and reduces the power required to spin them, HGST said. The helium hermetically sealed within the drive also contributes to less turbulence and less heat buildup inside the drive, it said. The first customers for the high-capacity drives are expected to be corporate and institutional clients with massive storage needs. Video streaming giant Netflix has reportedly been testing the drives. "We serve billions of hours of streaming video per quarter to over 40 million subscribers," David Fullagar, Netflix director of content delivery architecture, told Fox News. "The high storage density and lower power usage of the Ultrastar He6 hard drives allow us to continue with that goal, and create a great customer experience." HGST has not announced a price for the drive.