In addition, the inherent benefits of the platform, including the helium fill, allow HGST to significantly improve datacenter TCO on virtually every level: capacity, power, cooling and storage density.

ENGADGET: HGST develops helium-filled, high-capacity hard drives: no, they won't float away

As one of America's greenest banks we plan to take full advantage of the additional capacity and advanced power and cooling capabilities unique to zEnterprise.

ENGADGET: IBM's zEnterprise architecture makes mainframes cool again, also efficient (video)

The racks would rarely be nearing physical capacity, but might actually be maxed out in logical capacity due to power or cooling constraints at the rack level (the mantra to avoid creating hot spots in data centers has actually made floor and rack use a lot less efficient).

FORBES: The Case for the Infinite Data Center