If you just need a basic USB flash drive, it’s ok to just buy pretty much any drive. However, if you want a fast drive or a drive with special features such as encryption, buying a drive can get a bit tricky. Here are some of the things you should consider.
Flash Drive Capacity
An old sysadmin rule-of-thumb says “buy twice as much drive as you think you need.” That’s because files and programs tend to get bigger every year, so a drive that’s just barely sufficient today probably won’t hold everything you need tomorrow.
As of this writing, flash drives are economical up to about 128 gigabytes. Larger drives compete with true solid state drives as well as traditional magnetic disk drives, so unless you need a high-capacity drive in a USB drive format, consider the other options.
Flash Drive Speed
Any drive which doesn’t advertise its read speed and write speed should be considered a cheap drive. Cheap drives are fine—especially if it’s a drive you might lose—but you may not want to use a cheap drive for important files or large files that will take forever to copy at slow speeds.
The two main speeds to consider are the read speed and the write speed. Depending on how you use your drive, you’ll place a different level of importance on each speed:
- If you frequently copy files between computers (especially large files or many files at the same time), you’ll want a drive with both high read and write speeds. The faster the speed, the less time you’ll spend staring at the copy dialog.
- If you rarely add files to the drive but just use it to carry around documents or music, you still want a reasonable read speed (about 10 megabytes per second or faster), but a slow write speed won’t slow you down too much.
With that in mind, here’s a quick table of what to expect from read and write speeds in terms of MegaBytes Per Second (MBPS):
|Read (MBPS)||Write (MBPS)|
|Traditional Magnetic Hard Drive (For Comparison)||120||120|
|Quality Solid State Drive (For Comparison)||500||400|
|Cheap USB Flash Drive||8||2|
|Mid-Range USB Flash Drive||25||10|
|Good Flash Drive||40||20|
|High-End USB 3.0 Flash Drive||200||100|
As you can see, high-end USB 3.0 drives are much, much faster than cheap USB flash drives, but they’re still less than half the speed of a quality solid state drive. The good news is that USB 3.0 drives are rapidly dropping in price, so they’re now affordable for many more purposes.
Physical Flash Drive Size & Shape
Flash drives come in all sorts of sizes and shapes. You’re probably familiar with the standard shape, which is roughly the size of an adult male thumb (hence their nickname, thumb drive). There are now several other common form factors:
- Direct Inserts: these are flash drives that have no outside plastic case or cover for the plug end. They often have a metal case and the drive is directly inserted into the USB port. They tend to look quite stylish and can be placed on a keychain. Their only drawback is that dirt and other elements can get into the plug end and cause problems—but this isn’t much of an issue for drives that spend most of their time indoors.
- Mini Drives: these tend to be barely larger than the USB plug itself—in fact, there are a few which require pulling on a cord to remove it from your computer. These are perfect for anyone who plans to keep the drive permanently attached to a device—I use them to add storage to my netbook and to hold the MP3s for my car radio.
- Shaped Drives: many companies make drives in various shapes—my favorite drive of this sort is the American Express USB drive pictured to the right. But be careful of these drives: most of them fall into the cheap drive category, and some of them take up more space than a standard thumb drive, so you may not be able to fit them in some computer USB ports. (You can always use an extension cable.)
Some drives have special features, the main one these days being encryption to prevent other people from reading your files. You don’t need a special drive to use encryption—you can just install encryption software on your computer—but drives with built-in encryption may be easier to use on multiple computers because you don’t have to install the software first.
The quality of the encryption on different drives varies from weak encryption any technically-minded adolescent can beat to military-grade encryption that even the U.S. National Security Agency (NSA) probably can’t beat. The problem is that every company claims their product is very secure—but the only way to verify that is to have actual security experts examine the drive.
My recommendation is to look for encrypted drives with lots of reviews, and then carefully read the reviews looking for ones written by security experts. Alternatively, look for a drive that has passed a review board, such as a U.S. Federal Information Processing Standard (FIPS) 140-2 level 3 test.
These days everyone needs a good secure place to store files, and an encrypted flash drive with its own buttons is as easy to use as an ATM machine, so they make great gifts for the people you know who wouldn’t otherwise bother to install and use encryption software on their computer.
There are some other special features available for special purposes, such as drives that are water resistant or waterproof for people who do a lot of outdoor computing.
Flash drives come in a huge variety, but despite the prevalence of file transfer technology like Dropbox, flash drives are still the number one way to move files between computers. They’re essential, and it’s often nice to own several in case you have to lend one out. Just make sure you buy a drive that suits your needs.