Do I need to buy a USB 3.0 cable, or are they the same?
 
Thanks,
J

Well the 2.0 and 3.0 cables are different, very different, in fact and you don't want one if you have a 2.0 device. So USB3 has 5 additional pins to provide the high speed full duplex data connection. On the "A" side, the one that goes in to your computer, they are hidden in the back so you don't have an issue. You can plug a 3.0 cable in to a 2.0 port and it works fine (just only at 2.0 speeds) and a 2.0 cable in to a 3.0 port and it works fine (again only at 2.0 speeds). However on the "B" side, the one that goes to your audio card, it is different. The 3.0 cable has an additional part on top with the extra pins in it. So a 3.0 cable won't fit in a 2.0 device.
 
So, for 2.0 devices, keep using 2.0 cables, regardless of the port you plug them in to on the computer. For USB 3.0 devices you want to get a new cable, because it won't be able to use the higher speeds without it. Of course a USB 3 device should come with a USB 3 cable anyhow.

Recapping,
USB 2 cables will fit into all USB 3 connectors on both sides, but you will be limited to USB 2 speeds.
USB 3 cables look the same on the computer end but different on the device end.  You must use them for USB 3 speeds on USB 3 devices.

Also, be careful with using some USB 2 devices on USB 3 ports.
 
My NI Maschine created an issue where my computer got stuck in a bootloop if I started my computer with it plugged in to a USB 3 port.
 
I've since fixed the issue with a BIOS update and by changing some settings in the BIOS, but keep that in mind.
 
-Ki
Salem Beats

Thanks

Also you dont say what said usb 3 port is being used for, if its an audio interface check google for how it runs on usb 3 ports, some interfaces dont appreciate a usb 3 port at all :)

For a year I used my touch screen on a USB 3 port, but I've switched it to a 2.0 port now. Actually, I'm not using any of my 3.0 ports at this time.
 
Things would go funny with the monitor in the 3.0 port. Windows would try to set up the monitor to run without the monitor cable or something, and the sound would stop working in the monitor.
 
IDK what was up, but decided that MS was making changes that the driver wasn't keeping up with and that it just wasn't worth the trouble. My interface is supposed to be USB 3 compliant, but I feel it's safer to use it on a 2.0 port.

I recently (about 3 months ago) replaced my motherboard.  The current board has mostly USB 3.0 ports on the rear I/O panel.  My case has USB 3.0 ports on the front panel.   I'm running all my recording devices, which are either USB 1.1 or 2.0 devices in the USB 3.0 ports.  They all work without problems. 

It depends on the manufacturer of the said usb 2.0 device, my focusrite VRM box thing works fine on USB 3 but try runnign a line 6 usb interface on a usb 3 port and you will run into issues, I believe tascam are another offender too, most seem to be wising up and fixing it as it seems to be driver related.

My Line 6 POD XT and POD X3 both work OK with the USB 3.0 port.