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Can a USB 3.0 pen drive be used on a USB 2.0 port?

I am really excited about USB 3, especially since it has made its way into the new MacBook Airs and Pros. Since it is much faster than any other interface, I really want to get an USB 3 external drive. However, I am a bit concerned about the backwards compatibility. Is USB 3 backwards compatible? For instance, if I plug a USB 3.0 device into a computer with USB 2, will the drive work?

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marked as duplicate by Ƭᴇcʜιᴇ007, slhck, Dennis, Canadian Luke, RedGrittyBrick Jun 16 '12 at 20:00

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

Yes, a USB 3.0 external drive will work on a USB 2.0 port.
Very broadly, if the path from your drive to the system USB port has one non USB 3.0 component,
the interface will fall back to USB 2.0.

USB 3.0 Drive ==> USB 3.0 cable ==> USB 3.0 Port on Device

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It's backwards compatible. Your existing USB 2.0 gear will work on version 3.0 ports and vice versa. You'll be able to maximize your bandwidth when using a USB 3.0 cable with USB 3.0 devices and ports, otherwise plugging a 3.0 device into a 2.0 port or a 2.0 device into 3.0 a port will get you standard USB 2.0 data rates.

Since the new interface has been carefully planned from the start to peacefully co-exist with its predecessor, the connector itself remains mostly the same with the four USB 2.0 contacts in the exact same location as before. Extra pins for the new lanes dedicated to transmit and receive SuperSpeed data are located on the back and only come into contact when mated with a proper USB 3.0 port.

10 things you should know about USB 2.0 and 3.0 from December 2009.
More details at this FAQ and the Wikipedia article on USB.

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It will work but you will still be limited to USB 2.0 transfer rates. To get the increase speed you would also need a USB 3.0 port in your computer.

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Which are readily available and make backup to a USB 3.0 external drive much quicker. – Fiasco Labs Jun 16 '12 at 21:07

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