USB 3.0 compatible with USB 2.0

deerpark243 · 01 Nov 2012

I just bought a Dell XPS 8500 and it has 3 3.0 usb ports. My Western Digital external hard drive is usb 2.0. I bought a usb 3.0 cable and the mini side to the external hard drive seems to fit but it's really tight, am i suppose to have a converter or is it ok to run like it is? And is it damaging my external hardrive or my pc running it this way?and by doing this would it just run at a usb 2.0 speed? sorry for so many questions, I'm new here.
Deerpark243

Christian Smith · 02 Nov 2012

Hi there,

If your External hard drive is a USB 2.0 device, you will not see an increase in performance by plugging it into a USB 3.0 socket on your computer. There will not be an advantage to you using a usb 3.0 cable in your USB 2.0 device either. I would use your original cable that came with the external hard drive.
Unfortunately you will be stuck on usb 2.0 speeds as far as I am aware.

deerpark243 · 02 Nov 2012

Thank you Mr Smith...

MilesAhead · 02 Nov 2012

Afa the speed goes, try the USB 2.0 cable and see how it goes. I have a 500 GB Seagate USB 2.0 external. I bought a couple of SIIG USB 3.0 cards and USB 3.0 docking stations. While I was waiting for the docks to arrive I plugged the Seagate into the SIIG. I got at least a 15% increase in sequential read/write speeds. Copying a GB file on was consistently 24 MB/s when plugged into a USB 2.0 port. Plugged into the SIIG I was getting transfers consistently in the 28 to 31 MB/s range.

But USB 3.0 tends to vary quite a bit. I've seen a lot of people with USB 3.0 native to the machine, complain they weren't very fast. You might get lucky like I did though. :)

Phone Man · 02 Nov 2012

Per the USB 3 specs, the USB 3 ports has both USB 2 and USB 3 wiring. On this diagram pins 1-4 are for USB 2 and 5-9 are for USB 3 and the controllers will determine what to use. It will use USB 3 if available on both ends and will use USB 2 as a fallback.

USB 3.0 compatible with USB 2.0-usb-3.png

Jim

deerpark243 · 02 Nov 2012

Thank you Phone man. So I will still need an adapter for my external drive usb 2.0 mini port?Or is there such a thing?

Thank you

MilesAhead · 02 Nov 2012

Unless I'm missing something. You have a USB 3.0 port on the PC. You have an external USB 2.0 HD. Plug the USB 2.0 cable that came with the HD into the USB 3.0 port. That's what "backward compatible" means. That's all I did with my Seagate external.

deerpark243 · 02 Nov 2012

I have a mini USB 2.0 on my external hard drive. I have 3 3.0 USB ports on my PC.So l inserted the mini 3.0 USB into the external USB 2.0 mini port. And seems to be working OK but I don't think it is at 3.0 speed. Sorry for the confusion.(and the regular size USB 3.0 into my PC).

MilesAhead · 02 Nov 2012

You have it backwards. I feel like I'm banging my head against the wall. USB 3.0 ports, you just plug the USB 2.0 connector in. It fits just as if the port was a USB 2.0 port. You can't tell by looking except the connector has a blue plastic strip inside instead of white. You will not get USB 3.0 speeds. But you may get better than USB 2.0. Then again you may not.

Just use the cable that came with the HD. I think this is the third time so I'm done.

deerpark243 · 02 Nov 2012

Sorry i'm annoying you, I have it set like you said and it seems like it is a lot faster.

Deerpark243

USB 3.0 compatible with USB 2.0

USB 3.0 compatible with USB 2.0

Adapters