Helping people with computers... one answer at a time.

Using USB 3 on a USB 2 computer is absolutely an option! There is a lot of compatibility built into the way USB is designed.

Leo, can I buy a one-terabyte drive, USB 3.0 and have it work on my computer with a 2.0 USB?

In this excerpt from Answercast #79, I look at the compatibility built into USB 2 and USB 3 ports and devices.

Using USB 3 on a USB 2 computer

Fortunately, the answer to this one is nice and clear, "Yes, you can!" In fact, it reminds me of a small story that I ran into myself.

I actually purchased a one-terabyte external drive - one of my Seagate Free Agent drives that I recommend regularly. I received it and plugged it into a computer.

I didn't really think that much of it. I did the usual formatting and backup and so forth.

Sudden speed increase!

I'm now using it on my Mac as my backup drive for the Mac's backup program. And I noticed that the backups were actually being very, very fast. Much faster than I expected.

As it turned out... I suddenly realized that this particular MacBook Pro that I have (it's one of the Retina models from earlier this year) actually has USB 3 support!

What I didn't realize is that the USB 3.0 compatible device that I had just purchased actually had a USB 3.0 device to plug into - in the form of my Mac; and it's working out very, very well.

USB 2 can run USB 3 device

The device will still connect to my USB 2.0 supporting devices just fine and I can do whatever I need with it.

So, the short answer is yes. The longer answer is yes, absolutely.

There's lots of compatibility built into the way USB is designed and this happens to be one of them. It's a very easy in fact to overlook. In fact, the device you have may be running at a higher speed than you think!

(Transcript lightly edited for readability.)

Article C6140 - December 16, 2012 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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7 Comments
Julian Adams
December 18, 2012 12:34 PM

I recently purchased a 2-Port USB 3.0 PCI Express Expansion Card which fit an unused PCI Express slot on my three-year-old Dell XPS 8000. I also purchased a 2 TB Seagate external hard drive which I use with Macrium Reflect. It now takes only about one-third to one-half the time to backup my computer vs. the time it used to take. Total investment was only about $120.

Harvey Smith
December 18, 2012 4:45 PM

Of course, your right, a USB 3 will work in a USB 2 slot, the only thing you didn't mention is the it will only work at the slower USB 2 speeds. But, you will be ready when you do upgrade your computer and the speeds do make a lot of differents. You will really note this when working with really big files, like videos, complete backups, etc.

BobS
December 18, 2012 5:24 PM

I'll just add if I may a word of warning about cables: A USB3 drive will only accept a USB3 cable at the drive end, but the USB end will plug into USB2 or 3. USB3 ports are colored blue.
Also, I recently had a problem with a 340GB USB2 drive: it took a few minutes to be recognized by windows, and then it reported some files were missing, couldn't be found even though listed. Also I could not scan it, check it or defrag it. So, after a few attempts I tried it on a different computer, it worked fine. But I tried it with a different cable too, and the cable was the only problem. I bought a new USB2 cable and problem solved! So before panicking or ditching a suspect USB drive try a different cable!

snert
December 18, 2012 7:05 PM

I know about the backwards compatibility of USB 3 to USB 2. There's tons of info all over the 'net. My question is - what, if ever was USB 1?

Phill
December 19, 2012 3:27 AM

External usb 3 drives wll work into a usb 2 pc system, the port in the external drive will accept usb 3 plugs or usb 2 plugs.

Mark J
December 19, 2012 9:42 AM

@Snert
USB 1 was around in the late 90s. It was soon superseded by USB 2.0.

James
December 20, 2012 6:25 PM

USB 1 was slow. I maintain a computer that only has USB 1 ports. When I need to copy files to/from my USB stick, it takes a lot longer than when I copy the files to/from my laptop.

I, like Leo, wasn't aware of USB 3 until I got my external HD this summer. I was disappointed to find out that my 6 month old laptop did not have USB 3 ports. So my backups are not lightning quick.

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