I currently have USB 2.0. Can I upgrade to 3.0? Does upgrading require new hardware or is it all software?
Do I even need 3.0? What are the advantages?
I’m just a home computer user but have this outrageous need for the latest and greatest! 
Thanks, Jack
If you have the need for the latest and greatest, you’re about four years late, because USB 3 devices came on the market in 2008.
In any case, if you want USB 3, you’ll need to upgrade your computer’s hardware to support it. Most computers have USB integrated into the motherboard these days, so that means getting a new motherboard. Alternatively, you can get a USB host adapter, like this one. (Assuming you’ve got a free PCI-express slot.)
Your USB 2 and even USB 1 devices will work fine on a USB 3 bus, but they won’t get any speed advantage.
USB has nothing to do with software whatsoever. USB 3.0 is much faster than USB 2.0, but it’s completely compatible. It’s also not going to do you any good if you don’t have any device that take advantage of it - a USB 2.0 external harddrive on a USB 3.0 port is not going to be one iota faster, just like a USB 3.0 harddrive on a USB 2.0 port. If you get a new computer, make sure it has USB 3.0, but don’t bother upgrading unless you move around a lot of big files.
Thanks. I kinda thought that, but now I know.
As a SW engineer who is debugging USB issues, I tend to disagree with some of this. It definitely has SW impacts, although the protocol side might not be too different. I believe the USB 3.0 spec calls for more pins. I know it allows for a higher current draw, although that’s handled by increasing the amount allowed per unit. It’s not completely compatible, but the differences are manageable without understanding the details.
I do agree that you probably shouldn’t upgrade for the sake of upgrading. I haven’t seen many 3.0 devices, and have no pressure to support it on the products I’m aware of.
-D/a
In that case, maybe you could enlighten me about a problem I had where the two were indeed not completely compatible:
I recently got a new MacBook Pro with two USB 3.0 ports. Everything worked fine, except for a little DJ mixer and a USB sound interface, both of which just didn’t want to do the job properly - until one day I inadvertently plugged them into a passive USB (2.0) hub, which caused them to function perfectly, which they do to this day. What could be the cause of that? It seems almost like an appliance that doesn’t work on a wall outlet, but does on an extension cord. (I know it’s not the same.)
If you back up your computer (you do back up your computer don’t you?) to an external hard drive you want USB 3. It will turn backing up from an overnight and then some task to something you can do over lunch.
Other than external storage and perhaps expensive web cameras, there is little benefit to USB 3.0 for the average person.
USB 3.0 is a superset of USB 2. As noted above, the connector adds 4 new pins. It is these new pins that provide the extra speed. USB 2 uses four pins, power, ground, and a +/- signal pair. USB 3 adds two high speed pairs, one for transmit, one for receive. The original (lower speed) signal pair remain and provide backward compatibility for USB 1 and 2.
Clearly, unless both ends of the connection are USB 3, there is no mechanism to take advantage of the new signal wires, and you get, at best, USB 2 functionality and speed.
USB 3 is a lot faster than USB 2. It does make a difference for disk transfers.
Interesting. I could speculate that the 3.0 port wasn’t happy with not having a full 3.0 device attached, but it’s supposed to work. I haven’t developed a device with 3.0 yet, so I’m not really up on the quirks. I only know some of the theory. Sorry.
Yes. Exactly, and well put.
-D/a
So I was just talking about this at work. We make a USB-to-serial cable that needs a driver, and apparently the driver doesn’t work with USB 3 ports.
I thought the backwards compatibility was inherent in the standard, so that a device with USB 3 ports would “just work” with USB 2.0 devices.
Is there some sort of autonegotiation procedure that has to happen in software that requires new drivers to talk to USB 3.0 ports?
My guess is the driver just needs to be updated to talk to newer USB3 controller chipsets. I’m sure the physical port will still work fine.