All About Read and Write Speeds

And a Discussion of Solid State (SSD) vs Hard Disk (HDD) Drives

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All About Read and Write Speeds

When it comes to external and portable hard drives, such as computer storage devices like hard disk drives (HDD), solid state drives (SSD), and storage area networks (SAN) -- and USB flash drives (which can be viewed as small SSDs) -- a measure of performance are read and write speeds. Here we’ll break it down as simply as possible.

The read speed is how long it takes to read something from the drive, or how long it takes to open or read a file that’s stored on the drive.

The write speed is how long it takes to save something on or write to the drive.

Megabytes per Second

Read and write speeds are typically recorded with the letters “ps” at the end of the measurement. For example, a drive that has a write speed of 32MBps means that it can record 32MB (megabytes) of data per second.

There are various sites on the web that allow you test read and write speeds, as well as sites that help you convert various measurements.

SSDs are the Fastest

Solid state drives have the fastest read and write speeds, outpacing hard disk drives. Here are a few of the fastest SSDs and their read and write scores:

Samsung 850 Pro

Available Capacities: 128GB – 1TB
Interface: SATA III 6Gbps
550MB/s read (256GB)
520MB/s write (256GB)

SanDisk Extreme Pro

Available Capacities: 240GB – 960GB
Interface: SATA 3 6Gbps
550MB/s read
520MB/s write

Mushkin Striker

Available Capacities: 240GB – 960GB
565MB/s read
550MB/s write

Corsair Neutron XT

Available Capacities: 240GB – 960GB
560MB/s read
540MB/s write

HDDs are Slower But Cheaper

Corsair Neutron XT

Hard Disk Drives, or HDD in techno-parlance, were first introduced by IBM in 1956 - yes, 60-year old technology. An HDD uses magnetism to store data on a rotating platter. A read/write head floats above the spinning platter reading and writing data.

The faster the platter spins, the faster an HDD can perform.

HDDs are slower than SDDs, with an average read speed of 128MB/s and a write speed of 120MB/s.The cost is about $.03 per gigabyte versus an average $.20 per gigabyte for SSDs