Solid State Drives 101: An Intro to SSDs


One of the more noticeable, yet unnoticed, shifts in the way computers are being made as of late is the new trend toward the use of solid state drives. The claim is that a solid state drive runs faster and more reliably than a traditional, platter-based hard disk drive, and is thus ideal for today’s speed-and-durability oriented computers. However, most consumers see the relatively high prices of solid state drives as a turn-off without actually knowing the true differences between a hard disk drive and a solid state drive. We’re here to give you a basic primer on the differences between an SSD vs. an HDD.

Out with the old…

It is worth it to begin by exploring the technology that has been used for years, the hard disk drive. Innovated by IBM in the 1950s, hard disk drives have stayed about the same in terms of construction and principle for decades. A certain number of spinning metal platters, shiny with a magnetic coating, spin inside of the hard disk drive and are written to, and read by, a moving arm with a small head, similar to a record player.

Those platters can each hold a specific amount of data, so while companies have pushed to increase that amount of data that can fit on a single platter, they have also added platters to increase the capacity of a hard disk drive. Commonly retailed hard disk drives usually top out at about 4 TB, or 4,000 GB, of capacity on a single drive.

Though hard disk drives are the current norm in terms of major storage, they are not without flaws. They can be noisy, they are more easily damaged than SSDs when being transported, and a misplaced magnet or electrical charge can fry every bit of data that’s on the drive. Any new or innovative technology has these primary issues to tackle.

…in with the new

A solid state disk shares many commonalities with a traditional hard disk drive, but the differences between the two are what is key. An SSD has no moving parts, and instead of storing data on spinning platters, it stores the data on individual flash memory chips, akin to the ones found inside of a flash drive or smartphone. Those chips are faster than those found in USB drives, and have much more capacity and long-term durability in terms of data cells.

An SSD also needs no power to store its data after shutting down, which was a problem that had plagued many hard disk drives until fairly recently.

Fragmentation is another issue that solid-state drives deal with much better than HDDs. Traditional hard disk drives will split up, or “fragment,” files to make them fit on the drive if the file itself can’t be written as a single thread of data on one platter. When these files become fragmented and the drive is filled with more information, the drive then requires more time to access, read, or write data, because it is not contained in a single contiguous block. SSDs do not suffer from this problem, and even in the event of minor fragmentation, they can resolve the issue faster.

In the status quo, SSDs are not commonly offered with as much storage capacity as traditional HDDs, and in the rare case that they are, SSDs are much more expensive. We examined three key types of drives (3.5″ and 2.5″ hard drives, and 2.5″ solid state drives) and compared their prices based on cost per gigabyte.

Based on loose averages, this is what a 250 GB drive costs for each type of drive:

2.5″ HDD @ 250 GB = $50 = 20 cents per gigabyte
3.5″ HDD @ 250 GB = $70 = 28 cents per gigabyte
2.5″ SSD @ 256 GB = $200 = 78 cents per gigabyte

Admittedly, the drive prices above are conditional and not exactly precise down to the cent. However, a little consumer research will illustrate that the prices above are very close to the median price for the drives being sold by online retailers.

Based on those prices above, a 1 TB SSD could cost nearly $800, whereas a 1 TB laptop hard drive might cost less than $100. The prices above show that, if you wanted a new 2.5″ drive to replace the drive in your laptop, you would pay almost quadruple what you’d pay for an HDD to get an SSD.

So are SSDs worth the cost?

That question depends entirely upon the tasks for which a consumer uses their computer.

An SSD is ideal for people who want portability and are constantly moving, chucking their laptop into their bag or are generally clumsy or reckless with their gadgets. Because of the lack of moving parts and the general durability of SSDs, they don’t break as easily when dropped.

SSDs also load programs, read and write data much faster than HDDs do, making them ideal replacements for older laptop drives with the same capacity. An SSD delivers the most bang for your buck when it comes to a single upgrade you can make to your laptop or desktop, because it brings with it speed that is physically impossible for a hard disk drive to achieve with platters and an arm.

An apt analogy for this difference is to think of an SSD like a part, and a hard disk drive like a machine. A hard disk drive needs time to speed up to full operating capacity, to boot its operating system, and can only handle a certain amount of data-driven processes at any given point. An SSD works within a machine, allowing data to come and go freely without any physical road blocks. Whereas an HDD has to take the load on its shoulders, an SSD is more like a conduit that makes processes move more quickly.

Since SSDs are still a fairly young technology and are so costly on a per-gigabyte basis, they only come in smaller capacities for the time being. Terabyte SSDs do exist, but they are not very common and are immensely expensive. Most common-market SSDs top out at around 250 – 320 GB.

Because of this fact, those who use large amounts of data or work with files that are particularly sizable would not necessarily benefit from upgrading to an SSD. Video editors, photographers, and other folks whose professions involve large pieces of data may like to hear that an SSD will boot AfterEffects or PhotoShop faster, but that’s of no benefit when there’s no room for the files.

This issue will likely come to pass soon at the rate at which solid-state technology is being innovated, as well as cloud computing continues to become more feasible, but until that happens, HDDs are likely to remain the norm. SSDs are not uncommon – many Ultrabooks use them as their main drives, and many computers use dual HDD/SDD setups that hybrid the two types of drives into a cohesive storage unit.

Until the cost of solid-state drives can come down to a competitive margin, and once their available capacity increases, mechanical hard disk drives will likely retain the lion’s share of the world’s internal storage. They avoid or remedy the problems that plague hard disk drives, but are plagued themselves by higher costs and limited storage space.

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