Serial ATA hard drives, also known as SATA drives, have been a staple of computer storage for many years, and as of the time of publication continue to be one of the most commonly used forms of data storage for laptop and desktop computers. However, solid state drives, known as SSDs, have increasingly become popular, especially as a form of high-capacity portable storage. While both technologies are forms of hard disk storage, there are a number of key differences between them.
Technology - SATA HDD
Typical SATA hard disks consist of a spindle with a flat, circular disk called a platter. The platter is made of a non-magnetic material, with an extremely thin coating of magnetic material over the top and a layer of carbon protection. This spindle is motorized and spins the platter at high speed, allowing read and write heads on an actuator arm to magnetize areas of the platter to store information.
Technology - SSD
On the other hand, solid state drives have no moving parts, as they are essentially a microchip consisting of a memory system and a controller. Memory types vary depending on the type of SSD, but generally fall into two categories -- DRAM and flash-based. DRAM SSDs work similar to a RAM memory chip, operating with incredible speed but with no data persistence during power loss, either by shutdown or power outage. This loss of persistence is often mitigated by incorporating an internal battery or an external AC/DC power adapter and backup storage systems to the SSD. Flash-based SSDs maintain data persistence and do not require a separate power source, but also are slower than their DRAM counterparts.
Wear and Lifespan
Another key difference between SATA drives and SSDs is their operational lifespan. Because they rely on moving parts to function, hard disks are subject to wear and tear over the span of their operational lifetime. As a result of this wear, SATA hard disks will eventually wear out and cease to function. With no moving parts, SSDs are subject to considerably less wear, and have a much longer lifespan than hard disks, barring catastrophic damage from external forces.
As a result of the reliance on moving parts, SATA hard disks are also considerably more likely to be damaged by environmental factors such as extreme shock and vibrations. Also, because hard disks employ magnetic technology to encode and read, they are more vulnerable to electromagnetism and radiation. SSDs are considerably more durable and have much higher tolerances for these factors, although they are not entirely immune.
Power Consumption and Heat Dissipation
SATA hard disks also consume more power than an SSD. Not only is power needed to read and encode the data, but the mechanical components such as the motorized spindle and the actuator arm also require power to function. This additional power usage and motion has another side effect -- heat generation. The heat generated by a SATA drive needs to be dissipated to prevent damage to the hardware. This is usually accomplished with a fan, although some systems employ other cooling methods. By comparison, the SSD requires very little power, as it has no moving parts to operate. The lessened energy demand and the lack of moving parts also reduces the amount of heat the SSD generates, reducing the need for heat dissipation.
SATA drives run much louder than an SSD. This is primarily because of the moving parts. The spindle motor typically runs anywhere from 3,000 to 15,000 revolutions per minute, depending on the set speed of the disk. This can make quite a bit of noise. The SSD doesn't move at all, and generally runs whisper-quiet by comparison.
As of the time of publication, SSDs are considerably more expensive than their SATA counterparts. While more SSD technology is becoming readily available, it is still considerably more expensive than SATA. Depending on the part's brands and capacities, it may be possible to install several hard drives with considerably higher capacity for the price of installing a single SSD. However, as technology continues to advance and SSDs continue to be produced in greater quantities, this price disparity will gradually shrink and eventually disappear altogether.
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