5. How The A.B.L.E. Power-saving Mechanism Works

Grossly oversimplified, the functioning of the A.B.L.E. can be explained as follows: Similar to mobile processors, hard drives can also assume different operating statuses (like active, idle, standby and sleep).

How a conventional power-saving mechanism works

These are characterized by a varying level of energy use. Switching between the individual power modes occurs depending on hard-drive usage and with fixed time-out periods ranging from seconds to minutes.

How an adaptive power-saving mechanism works

The adaptive battery life extender (A.B.L.E.), on the other hand, continuously logs hard drive usage. Taking into account the usage pattern, which has been saved, a software algorithm calculates the timeouts dynamically. The energy use of the hard drive therefore depends directly on the hard-drive usage of the moment, and therefore on user behavior. Thus on average, a lower energy use results than when power modes are controlled with fixed timeouts.

Summary: Choose The Faster Hard Drive Whenever Possible

For users faced with the choice between a standard 4200-rpm hard drive and a faster 5400-rpm or even 7200-rpm model, we would recommend picking the faster-turning drive. Although the battery life will be a few minutes less, the performance increase more than outweighs this relatively small downside. The mere fact that a notebook boots up faster when equipped with a 5400-rpm drive justifies the higher price, in our opinion.

Regarding noise levels, we could not determine any significant differences between the different drives.

Price, however, is an entirely different matter. The Hitachi 7K60 is about $60-$70 more expensive than a 5400-rpm hard drive with the same capacity and identical cache size. When buying a built-to-order notebook, the user should still consider whether to "save" a few hundred megahertz on the CPU in order to "finance" the faster hard drive.