Just when you thought hard disk drives were at the end of their lives as solid state becomes more affordable, Western Digital subsidiary HGST has given its drives new life, by adding helium.

The new Ultrastar He6 drives use helium instead of air to increase capacity up to 6TB. The 6TB Ultrastar He6 not only has greater capacity but it's also faster and more power efficient than normal drives.

Standard drives contain five platters rotating in filtered air. The Ultrastar He6 uses helium meaning less resistance thanks to the lighter and cooler gas. And the reduction in friction means temperature stays down so drives can spin for longer on less power. This has allowed for another two platters to be put in, to push storage up to 6TB in a single drive. All that and it should last longer and cost less to run too.

As if all that wasn't good enough there's more. Since the gas needs to be hermetically sealed in it means you can now drop the drive into water and it will still work. So you could store the drive in cooling fluid for even greater operating efficiency without any worry of damage.

The 3.5-inch, 640g drive will use 5.3 watts when idle. According to an IHS iSuppli analyst, Western Digital rivals will struggle to catch up as patent issues will be a problem. This doesn't bode well for competition and so we'd expect this to be a pretty pricey drive when it hits shops.