Is a pure USB 3.0 port fully compatible with USB 2.0 ? My question came when I want to buy a new motherboard. Some motherboards have USB specified as USB 3.0/USB 2.0 which clearly signifies that this port is USB 2.0 compatible. Some motherboards have their USB 3.0 ports specified as USB 3.0 only. Does that mean I might face some compatibility issues for some USB 2.0 devices? Does this differ from USB3.0/USB2.0 ports?

Thanks!

  • 2
    USB 3.0 ports are backward compatible with USB 2.0. When they describe it as USB 3.0/USB 2.0, the marketing people are just being explicit so that people who aren't aware are reassured. – fixer1234 Jul 19 '16 at 6:47
  • The problem is the same marketing people put USB3.0/2.0 on some models, and some other models have USB3.0, that what confused me a lot! – 3bdalla Jul 19 '16 at 7:12

Thing is in most cases it won't matter, usb 3.0 or 2.0, they will both work. But problems may occur. For example when I tried to unlock bootloader on my HTC One M7, I didn't work with usb 3.0 port, it had to be 2.0.

So yes, in 99,5% it really won't matter, but if you might operate with some a bit older devices on software level, you might want to get at least one usb 2.0 port.

  • ooh, that's odd. I wonder if its an ADB thing or a hardware thing. – Journeyman Geek Jul 19 '16 at 7:39
  • We work with many USB 2.0 instrumentation devices across many different PCs and although most will initially appear to work ok on USB 3.0 ports, sometimes there will be reliability issues that are solved by switching to a USB 2.0 only port. – SoftDeveloper Jan 10 '17 at 17:10

It'll just work. USB 2.0 devices or lower should work perfectly on USB 3.0. USB 3.0 devices will work slower on USB 2.0. The USB 3.0 socket has some extra pins that are just not connected with a USB 2.0 plug

USB 2.0 and 3.0 motherboard headers are completely different and you can't use a USB 2.0 front panel on a USB 3.0 motherboard header and vice versa. You may need an adaptor

USB 3.0 has been around enough that most compatibility issues should be worked out and well documented

USB Type C is an entirely different type of socket, and the cables/connectors won't fit a USB type A connector on a PC or a USB type B connector on a device. You may need adaptors for this.

  • So no worries at all when buying an MB that has USB 3 ports labeled as USB 3.0 not USB 3.0/2.0? – 3bdalla Jul 19 '16 at 7:15
  • None whatsoever. Considering that most mice/keyboards/mobile phones are USB 2.0, and connect via type A, dropping support for USB 2.0 would be... dumb. – Journeyman Geek Jul 19 '16 at 7:15

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