The hard disk drive industry is more complex than most people think. Sometimes, it feels like you need to be a hardware engineer in order to get a grasp on it. There are, essentially, three major hard drive manufacturers Seagate, Western Digital and Toshiba. That's easy enough to understand. What's not easy is figuring out the differences between the drives these major manufacturers and the differences between the hard drive lines that they produce.
External Hard Drive Limitations:
External hard drives come in two flavors, just like internal hard drives: solid-state drives (SSDs) and mechanical hard disk drives (HDDs). In fact, in most cases, external hard drives are the exact same drives you'll find in computers just with a plastic or metal enclosure. In the case of external desktop hard drives (read: not portable external hard drives), they also come with a built-in power supply.
External SSDs are very, very fast. However, they're also expensive, and you can't get them in large formats. For backups and media storage, HDDs are still the better option in most cases. This leaves us with a problem. HDDs are limited by their mechanical design. They can't perform anywhere near as fast as SSDs. It's just not possible.
In the past, external hard drive performance wasn't much of an issue, because they were often limited by interfaces, like USB 2.0. There were faster interfaces, like eSATA and FireWire, but there weren't many PCs with native ports for these. USB 2.0 was the bottleneck for many older external hard drives, so fast HDD performance wasn't particularly important.
Now, most external hard disk drives come with USB 3.0 ports. These ports are also common in laptops and PCs. With USB 3.0's much-improved bandwidth, the HDD is suddenly the bottleneck. If you want fast transfer speeds, then you need to be aware of what the external hard drive is capable of.
Western Digital My Book:
Knowing what an external hard drive is capable of can be quite difficult, thanks to the confusing nature of the hard drive industry. A prime example is the Western Digital My Book. For the most part, My Book does what it advertises and is one of the best external hard drives. What Western Digital doesn't advertise is that inside the enclosure of My Book, you can get several different HDD models.
What this boils down to is that your My Book may be slower than your friend's My Book, or vice versa, because they may not have the same HDD. Because mechanical hard disk drives aren't capable of using USB 3.0's full bandwidth, the drive's performance is much more important than it was when external hard drives used USB 2.0.
Does It Matter?
What you need to decide is whether external hard drive performance is important to you. If you're using the external desktop hard drive mostly as a backup, then you'd only notice a real difference when backing up or restoring very large files or folders. You might notice a larger difference if you want to stream HD content from your external hard drive.
In many cases, you're going to pay more for external hard drives that clearly post their specifications. Is having the absolute fastest external hard drive really necessary? If it is, you may want to look at external SSDs. HDDs are great for storage, but they haven't ever been particularly quick.
With this knowledge in hand, you'll be better able to make a good buying decision. The hard drive industry can be difficult to decipher, but it is possible. As long as you know what you're getting into, you can get the external hard drive that you want. You'll pay a premium for the fastest external hard drives (SSDs), and the options for HDDs aren't always clear, but one thing is certain: Having an external hard drive for backups is much, much better than not having one.