SSD Vs. HDD Power
Since the mid-2000s, solid-state drives have become less expensive, competing with traditional hard disk drives for the PC data storage market. Aside from their main advantage, speed, SSDs should in theory also have better energy efficiency than HDDs. However, tests comparing SSDs to HDDs have revealed that under some conditions, solid-state drives have an efficiency advantages, and in others, HDDs have an edge.
Other People Are Reading
-
Design
-
A hard disk drive's design uses a spinning metal disk and a read-write mechanism. The mechanism moves in and out radially along the surface of the disk, millionths of an inch above its surface. A magnetic sensor on the mechanism reads and writes magnetic data as the disk spins underneath it. Electronic circuits manage the disk speed, mechanism positioning and data movement. A solid state drive, on the other hand, has no motors or mechanisms, using gigabytes of flash memory in place of a spinning disk. Like the hard disk, a solid-state drive has interface and driver electronics, but no mechanical parts.
Operation
-
The motor that spins the disks in a hard drive, along with the read-write mechanism, make up for most of the hard drive’s power consumption. Computers, and laptops in particular, use sophisticated power management techniques to minimize the drive’s power needs. For example, a laptop’s energy-saver mode spins the disks only when needed. This makes the computer slower and less responsive for some tasks, but prolongs battery life. A solid state drive has essentially two modes: idle and active. An idle drive is ready for data access but is not currently storing or retrieving data. An active drive consumes more power, as it is processing data.
-
Rated Power Consumption
-
Rated power consumption for solid-state drives varies for different brands and models. Hewlett-Packard’s SSDs, for example, use 100mW at idle and 150 mW when active. Kingston rates its solid-state drives between 50mW to 700 mW at idle and 1,700 to 5,200 mW when active. By comparison, Western Digital’s Caviar Green series hard disk drives average about 6,000 mW when active and 5,500 mW when idling.
Tested Power Consumption
-
In 2008, Tom’s Hardware website compared battery life of notebooks running SSDs versus traditional HDDs and reported that the SSDs, under real-world conditions, used more power than HDDs. Their tests concluded that with low loads, HDDs showed better efficiency, and under heavy loading, SSDs were more efficient. The low loads reflect average PC and laptop usage, where the computer uses the drive occasionally to access files. Technology continues to evolve and improve, however, so new generations of SSDs will no doubt eventually have better efficiency across the board.
-
References
- Photo Credit Jupiterimages/Photos.com/Getty Images
