Data Backup. External Storage Archives

Why is SSD better for Data Backup?

If you need speedy local storage for lots of files (say, music or movies you carry around, or all those pics and videos you collect on your phone or camera), you may want to consider a portable solid-state drive (SSD) rather than a portable hard drive.

Once prohibitively expensive, SSDs of all stripes have been falling in price over the past few years, and external SSDs have emerged as alternatives to external hard drives, delivering as much as five times the speed and much greater durability. They have no metal platters to spin up, nor any read/write heads that need to travel to a specific point on a platter to find the file you need. And because of their lack of moving parts, portable SSDs are usually more compact, slimmer, and better suited to frequent travel and accidental drops than even the most thoroughly ruggedized hard drives.

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Unlike a hard drive, which stores data on spinning platters accessed by a moving magnetic head, a solid-state drive uses a collection of “persistent” flash memory cells to save data. These are similar to the silicon that makes up a computer’s RAM, but they retain your data when electrical power is cut off.

Since hard drives are mechanical devices that use mature technology, you can get relatively huge amounts of storage capacity for the money. But the same tech that makes hard drives a tantalizing value becomes their biggest liability when used on the go. If you drop the drive, you could damage the interior mechanism and make your data inaccessible. By contrast, if you jolt an SSD while you’re reading or writing data, there is no risk that your files will become corrupted and unreadable.

And, again, hard drives are slower because they have to physically access your data. Just how much faster is it to read data from flash cells than from particular points on spinning platters? Typical throughput for consumer hard drives is in the range of 100MBps to 200MBps. (One factor is spin rate—among external drives, 5,400rpm units are more common and more affordable than 7,200rpm.)

External solid-state drives are, essentially, internal SSDs (the same kind that power laptops or live inside desktops) with an outer shell. As a result, external drives use one of two internal “bus types” that, in part, dictate their peak speed: Serial ATA (SATA), or PCI Express (PCIe). The latter is usually associated these days with Non-Volatile Memory Express (NVMe), a protocol that is optimized for the characteristics of SSDs and speeds up data transfers.

SATA-based drives tend to be a little cheaper; they’re also slower, but just fine for most users’ everyday applications. SATA-based SSDs typically top out at around 500MBps for peak read and write speeds, just a bit below the ceiling of the USB 3.0 interface. (Much more about that in a moment.) However, if you’re going to be transferring large files such as videos often, you may well want to spring for a PCIe/NVMe-based external SSD. That also ties in with the port you’ll plug your SSD into.

Sellers of portable SSDs don’t always indicate if the drive is SATA- or PCIe-based. However, checking the specs can be a giveaway. If the drive tops out at sequential read and write speeds between 400MBps and 550MBps, it’s very likely SATA-based. Speeds of 800MBps or higher indicate a PCIe-based drive.

Here are three key things to look out for when shopping for an external SSD:

COST PER GIGABYTE. The way to calculate relative value on drives like these is to perform some simple math and figure the cost per gigabyte based on the price of a given drive on the day you’re shopping. Because SSD pricing fluctuates all the time, relative value does, too.

RUGGEDIZATION. The degree of ruggedness does vary from drive to drive, with drives like the ADATA SE800 leading the field at the moment among mainstream-price external SSDs. IP68 certification is a good spec to look for if you’re serious about waterproof and dustproof drives.

CARRY WEIGHT. Most SSDs weigh a negligible couple of ounces. I like the carabiner retention loop of SanDisk’s Extreme family of drives, as many of these drives are small and light enough that losing them is an easy and expensive mistake.

If none of the drives we’ve selected for this roundup sounds appealing to you (or you already own an internal SSD that’s hanging around the house or office), there’s one more option available: SSD enclosures. These are plastic or metal housings into which you can put your own SATA 2.5-inch or M.2 solid-state drive to take with you on the go.

Enclosures come in 2.5-inch form factors (into which you would put a 2.5-inch SATA SSD) or M.2 ones. The stick-style M.2 SSD is much smaller and lighter, but know that M.2 drives themselves come in both SATA and PCIe bus flavors. You need to be sure your enclosure supports the kind of M.2 drive you’re putting in it.

Though there are exceptions, most enclosures are not as durable or rugged as major-maker portable SSDs are. This can be a drawback for those who take their SSDs into dangerous environments (think wildlife photographers or first responders), so be sure that before you go this route, you know what your drive will be exposed to. Your data could be at greater risk for corruption than it would be in an SSD purpose-built to withstand the elements.