Not all USB drives are created equal

Performance and reliability vary, but getting product specs for flash drives can be tricky.

When USB drives do begin to fail, they do so one cell at a time, not across the board, says Crandall. This is why an SLC-based drive might be worthwhile for a user storing, say, a virtual machine on a flash drive to restore their system after a disaster, according to Wilkison. If the drive began to fail, dropped bits might not be noticed in a photo or music track but could crash the system if they disappeared from a key part of an operating system.

There are features in the I/O controller that can boost performance in USB drives as well. One is the use of multiple channels to simultaneously move data to and from memory, says Brad Anderson, director of product marketing at USB flash drive vendor Lexar Media. Another, he says, is interleaving, which intermixes data flows to and from multiple flash memory chips within the drive to ensure the channel is used to its maximum potential.

As with many other design details, it's difficult for consumers to determine which I/O controller is used in a specific drive and which features it provides. While a consumer could try to find out which I/O controller is used in a specific drive and investigate how that controller works, most buyers will, according to Wilkison, have to "extrapolate from the speed" of the drive what type of controller is in it.

No standard

Right now, possibly the only way to know whether you've bought a drive that uses SLC memory is how much it costs -- the more expensive the drive, the more likely it is to have been built using SLC.

There is one way to judge the quality of a drive besides the price: the Windows ReadyBoost logo, which indicates that the flash drive can be used to supplement system RAM and thus speed the performance of Windows Vista-equipped PCs.

However, the minimum specifications for Windows ReadyBoost are just 2.5MB/sec. for random reads of 4KB of data, and 1.75MB/sec. for random writes of 512KB of data, which Crandall says are typical of lower-priced and lower-speed USB flash drives. Customers who want the maximum benefit from Windows ReadyBoost should opt for a USB drive marketed as a high-performance device and probably priced at the high end of the average for its capacity.

The future

In the first half of 2009, Wilkison predicts, controller manufacturers will begin shipping drives with dual- and even four-channel controllers, which will increase speeds even for slower MLC memory by increasing the number of lanes through which data can be written to and from the memory cells. USB drives combining four-channel controllers with MLC memory will reach speeds of about 60MB/sec. for reads and 30MB/sec. for writes, coming closer to -- but not quite -- saturating the USB 2.0 interface.

For the average consumer for whom price is more important than speed or reliability, any reasonably priced USB drive should do. But if speed or longer life is critical, look for drives advertised as high performance, do your research online and expect to spend more. But even then, you can't be absolutely sure you're getting more speed for your money.

Join the newsletter!


Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Robert L. Scheier

Show Comments




Sony WH-1000XM4 Wireless Noise Cancelling Headphones

Learn more >


Back To Business Guide

Click for more ›

Brand Post

Most Popular Reviews

Latest Articles


PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers


This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang


It really doesn’t get more “gaming laptop” than this.

Jack Jeffries


As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr


The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?