Confused about USB 3.0 and 2.0

Alright, so I am getting real close to purchasing my new system and I noticed that there are two versions of the computer case I want to get, one that is a regular USB 2.0 capable and another that is USB 3.0 capable with USB 3.0 ports on the front. Now, if I get the case with the USB 3.0 capable with a motherboard that supports USB 3.0, can I still plug in USB 2.0 flash drives and plug and play devices and still have them work? Or will I have to find the USB 2.0 port at the back of the computer? I got a warning on PC part builder that:

ASRock H77M Micro ATX LGA1155 Motherboard has an onboard USB 3.0 header, but the Rosewill CHALLENGER ATX Mid Tower Case does not have front panel USB 3.0 ports

If I get the non 3.0 case, can I still use the 2.0 front ports?
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  1. USB 3.0 is backwards compatible with all of it's lesser data intensive variants. Should be no problem as long as things are connected up right.

    Mmm but I don't think it is the opposite. You might be able to find converter cables from 2 to 3 but to 3 to 2? Good question.

    But I still don't think there will be a problem, you should be able to still use those ports too. Maybe not with the usb3 header. Of if you do, you won't get the full bandwidth. I don't know exactly though, if you can use USB3 headers on USB2 ports like that.
  2. USB 1-2-3 can use any combination of host, cable and device, except for USB3 cable and non-USB3 device. This is because the USB3 cable has a bigger connector that won't fit in the USB2 devices. Any other combination is covered by the standards. While I have not tried, I would even say that a USB3 HDD would work on a USB1 host.

    As for USB3 headers on motherboards, I don't know if they are standardized (as USB2 headers). I've seen some cases which have USB3 loops which get out of the case and are plugged in the back connectors. My Asrock Z67 Extreme4 comes with a 3.5" bay for USB3 which, of course, matches my USB3 header. I think that in my manual they say to be really careful with a case header.
  3. @mathew7, so I'm not quite understanding what you are saying. Are you saying that USB 2.0 devices can go into USB 3.0 ports but that USB 3.0 devices can not go into 2.0 ports?
  4. Get the case with the usb 3.0 ports on the front. All old usb 1 or 2 items like usb drives or even a mouse or keyboard will work fine. The usb 3 port is fully compatible with all older usb 1 or 2 devices.

    Most cases just have the usb 3 ports route out the back of the case and plug into the back of the mother board. They are just an extension cord.

    Some new cases have the internal USB 3 header cable which is standard now.
    You can not plug a usb 1 or 2 case with an internal port header into a usb 3 board. It won't fit and I have never seen an adapter. Luckily every board i have ever seen has at lease 2 internal usb 2 headers and 1 internal usb 3 header.

    I dont know if a new usb3 hard drive would work with an old usb 2 computer. Chances are it will simply run at usb 2 speed but I have never personally tried it because usb 3 storage is still kind of pricey.
  5. The mother board you picked out has the internal connectors to run 4 upfront usb2 ports and 2 usb3 ports all at the same time.

    So really any case will work, the only question is do you want upfront USB3? If you dont care right now get the challenger case... You can always add a usb3 front panel to one of the dvd drive slots in the future. There are also some pretty cool usb 3 card readers with upfront usb3 ports for around 25 that will plug into the internal usb3 mother board header.
  6. dragonfly22588 said:
    Alright, so I am getting real close to purchasing my new system and I noticed that there are two versions of the computer case I want to get, one that is a regular USB 2.0 capable and another that is USB 3.0 capable with USB 3.0 ports on the front. Now, if I get the case with the USB 3.0 capable with a motherboard that supports USB 3.0, can I still plug in USB 2.0 flash drives and plug and play devices and still have them work? Or will I have to find the USB 2.0 port at the back of the computer? I got a warning on PC part builder that:

    ASRock H77M Micro ATX LGA1155 Motherboard has an onboard USB 3.0 header, but the Rosewill CHALLENGER ATX Mid Tower Case does not have front panel USB 3.0 ports

    If I get the non 3.0 case, can I still use the 2.0 front ports?


    Dragonfly22588,

    In response to your question; Backwards compatibility: USB 3.0 cables have more contacts and components; the host (A) and the device (B) sockets have been deigned with the ability to accept USB 2.0 connections. At first site of the USB 3.0 version you most likely will think to yourself; "how can this fit"? but it does, thus allowing new USB 3.0 devices to accept USB 2.0 legacy cables. :)

    more information on USB 3.0 can be found below:
    http://blog.ineedusb.com/2013/04/usb-20-vs-usb-30.html

    @iNeedUSB
    -WeHookYouUp
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