Wednesday, July 8, 2015

Which Type of Hard Drive Should You Buy?

For years, the only type of hard drive available was the traditional magnetic hard drive.  These drives contained several magnetic platters that spun at fast speeds with data written and read by small arms.  While these magnetic drives are still the most popular drives, solid state drives are starting to catch up.  Solid state drives eliminate the moving parts (which cause the majority of traditional hard drive failures) and replace them with memory similar to what is contained in flash drives.  However, any time you have an option, you have to decide which is right for you.  Here are some factors to consider when deciding between a traditional drive and a solid state drive:

Storage Capacity - Traditional hard drives have a slight edge here when considering storage capacity alone, but it is not much.  While traditional hard drives can currently store as much as 10 TB of data, most consumer-grade drives come in the range of 1-2 TB.  While I have seen solid state drives as large as 2 TB, most will hold around 250-500 GB of data.

However, the real storage capacity factor comes when you consider the price per amount of data stored.  When you consider the price per unit, solid state drives are much more expensive than traditional hard drives.  For similar-sized drives, the price for a solid state drive usually runs at least twice as much as a traditional drive.  If you are looking to store large amounts of data (such as a movie collection), then you will definitely want to store it on traditional drives.

Performance - Traditional hard drives require the arm to maneuver to the right place on the platter at exactly the right time.  If the arm gets there late, it has to wait for the next spin.  While these drives spin thousands of times per second, too much waiting for the arm to get in the right spot can slow performance.  This is especially true when a file's data is spread across the drive instead of being located in adjacent sectors.  Older computers solved this problem through "defragmenting", which moved files around to get them into adjacent sectors of the drive.  If you used computers in the 1990s or 2000s, you are probably familiar with this process.  Windows now defragments your drive automatically, so you do not need to schedule a time to do it.

However, solid state drives have the edge in performance, even against a defragmented traditional drive.  They are designed so that any sector of the drive can be accessed in the same amount of time.  While the difference may not be noticed as much on a single file, I noticed a definite difference when I installed a solid state drive and loaded a fresh copy of Windows on it.

Durability - Solid state drives have a slight edge in durability, especially for laptops.  Traditional drives have a lot of moving parts, and one of those parts may break or scratch the platter at any moment.  While it is rare, it is possible for a drive to be fully functional one moment and unreadable the next.  (It is much more common to have some warning--such as a noise or burning smell--before a drive goes bad.)  By eliminating the moving parts, solid state drives are safer, but they can wear out, especially if you are saving a large amount of data to it.  However, studies have shown that solid state drives can last for at least twenty years under normal use in a personal computer.  Even if it only makes it to half that time, you will probably be ready to replace your computer anyway.

Which type of drive is better really depends on your needs.  If you need a substantial amount of storage, you will probably benefit from the cheaper price of traditional media.  If you value performance because most of your activity is online, you might want to consider a solid state drive.  You can also consider hybrid drives that make use of both types of memory or create your own "hybrid" by using one (or more) of each.

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