Investing in an external hard drive is the easiest way to add extra storage to your Windows PC or Mac to back up up your important files, adding extra capacity for games and media content, or creating a complete backup of everything on your computer.
After a months of digging, we found the best external hard drives on the market. However, not everyone works at a desk. If your lifestyle necessitates a portable hard drive, we recommend the G-Technology ArmorATD (available at Amazon), which is designed to take the beating that comes with being used on the go. Impact, water, and dust-resistant, it’s a fast external drive designed to stand up to casual abuse.
What You Should Know About Buying an External Hard Drive
Many people use hard drive as a blanket term for computer storage. However, there are some important differences, between hard drives and solid-state drives:
Hard drives store the data on a spinning metal-coated glass disk (called the platter) with a read-write head that moves around the drive, reading the magnetic data or writing new data. The biggest advantage that hard drives have over solid-state drives is that they cost significantly less, per gigabyte. However, they're comparatively fragile: the platter of a hard drive can be damaged if the drive is bumped or moved quickly while operating. Solid-state drives do not have this issue.
Solid-state drives (SSDs) store data in a computer chip, like a camera memory card. The advantage of SSDs is that they are faster and less liable to be damaged from rough treatment because there are no moving parts. While they have been around for a number of years now, SSD storage is still expensive, in comparison to the per-gigabyte cost of a hard drive.
Know Your Ports
Currently, there's no single standard for connecting an external hard drive to a computer. These are the ones that you're most likely to run into:
USB 3.2 Gen 1: USB 3.2 devices of both generations use USB-C sockets, which are small with rounded edges. If you have an older computer with old-style rectangular USB ports, USB 3.2 devices are still compatible with an appropriate cable. Most portable hard drives include cables for both USB-C and USB ports.
USB 3.2 Gen 2: The latest and fastest standard for how computers connect to external devices such as portable hard drives. USB 3.2 devices (like many of the portable hard drives we tested here) can send or receive data at up to 10 GB/sec, twice as fast as the previous standard
Thunderbolt 3 & 4: Another standard for how computers connect to devices. Thunderbolt 3 and 4 devices are compatible with USB 3.2 ports, as they use the same USB-C type port.
A Word on Hard Drive Speeds
Hard drives are complicated products, and there are a number of factors that can affect how quickly data can be read from or written to the drive. These include the type of data and the speed of the connection. It is slower, for instance, to write a lot of small files to a drive than a single large file, because the computer has to do a lot of background tasks to keep track of the small files.
The connection that the hard drive has to the computer can also make a big difference. If, for instance, you have a USB 3.2 Gen 2 drive connected to a computer that only has USB 2 ports, the data will take longer to copy because the USB 2 port will limit the speed at which data can be sent. While testing the external hard drives featured in this guide, we used a computer that supports USB 3.2 Gen 2 and Thunderbolt 3 so that we could see the best speeds that the drive is capable of. If your external hard drive is running slower than you think it should, check that it is plugged into the fastest port available, or consider upgrading your computer.
One of the most commonly mentioned features you’ll see associated with a hard drive is its revolutions per minute (rpm). This is a measure of how fast the platter that holds the hard drive’s data spins around. Some drives run at 5400rpm, others at 7200rpm. The latter can read and write data faster because of the higher speed.
2.5-Inch Hard Drives vs. 3.25-inch Hard Drives
There are two types of hard drives, indicated by the diameter of the hard drive platter that holds the data:
- 2.5-inch drives are designed for use inside laptops: they are small and don’t need much power. It’s these drives that you’ll find in most portable external hard drives. An external 2.5-inch drive can operate on nothing but the power supplied by the USB port it’s plugged into. The downside to using a 2.5-inch drive is that they can’t hold as much data as a 3.25-inch drive, with their larger platters, can.
- 3.25-inch drives were designed for use inside desktop computers, They are larger and more power-hungry. External hard drives that use 3.25-inch disks, such as the WD My Home, require an external power adapter in order to operate: a USB port simply can’t deliver enough power to run them.
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