USB 3.0 Tested: How Fast Is It in the Real World?

I've written a lot about USB 3.0, and finally I've been able to test an external USB hard drive in the real world. As I expected, I did see a big improvement in performance, but not nearly the performance numbers I saw in the demos at the Consumer Electronics Show.

That is partly because the speed of the USB connection is only one of many factors that impact real-world hard-drive performance.

The drive I tested was the Seagate Black Armor PS110, a 500GB, 7,200-rpm, 2.5-inch external drive. It comes with an Express Card USB 3.0 controller (based on NEC's internal controller). With a list price of $179.99, and features such as 256-bit AES encryption, this drive is aimed at enthusiasts and a business audience, since it's designed to be faster than the company's more consumer-oriented 5,400-rpm FreeAgent drives.

The Black Armor drive is designed for backing up laptops, with features including backup software and encryption. It can be attached to a USB 2.0 or USB 3.0 port, the latter of which looks the same but is electrically different, though backwards compatible. Because almost no machines come with USB 3.0 ports, the drive ships with an ExpressCard USB 3.0 connector and software that makes it work with a Windows laptop. Because ExpressCard doesn't carry as much power as USB, you also have to plug the card into a USB 2 port.

To test performance, I copied a subset of my photos and directories with 26.7GB of data (16,841 items) to the drive when it was connected to a normal USB 2.0 port and to the USB 3.0 controller. I also read the same data back to another directory on the host computer. For comparison, I tried the same tests with a 500GB FreeAgent drive. And since transfer speed will depend in part on the speed of the host computer, I tried it on two different laptops: a Lenovo Thinkpad T400s with an SSD and a Hewlett Packard Pavilion dv6 with a hard drive.

Here are the results I got. Note that "read speeds" means reading from the external drive and writing to the internal one, and "write speeds" are the reverse.