According to Tom’s Hardware, SSDs (solid state disks) consume more power than conventional platter-based hard drives. It seems the theory behind this is that when a SSD is in use it consumes power at its maximum not matter the activity, whereas a platter-based hard drive consumes its maximum power only when the head is moving.

What this means is that when your HDD is seeking, or moving the head to find the track the requested data is stored at, it consumes the most power, but once it has found the track the data is stored at it’s power consumption declines. In contrast when a SSD reads any data it pulls at its maximum rating. If your reading files from a conventional hard drive it will only pull its peak power for a fraction of a second (while it seeks), but once on a given track it takes less power (on average) to read data than a SSD would.

Tom’s Hardware tested several SSDs from seven manufactures and found a consistent bias towards SSDs pulling more power. It is claimed that this can have severe impacts on battery life for laptops. Only 2.5″ SSDs and platter-based HDDs were tested, no word on the 1.8″ SSD the MacBook Air uses, but it’s safe to assume all SSDs follow this pattern.

Read: Original Article on Tom’s Hardware.