USB 3 question


R

rfdjr1

I have a Western Digital My Book Essentials 500Gn external USB hard drive. My
machine has an ASUS motherboard which has two USB 3 plugs in the back. Should I
see any increase in data transfer if I plug the hard drive into the USB plugs or
does whatever you plug into USB 3 have to be specifically USB 3 itself? Thanks.
 
J

James Silverton

I have a Western Digital My Book Essentials 500Gn external USB hard drive. My
machine has an ASUS motherboard which has two USB 3 plugs in the back. Should I
see any increase in data transfer if I plug the hard drive into the USB plugs or
does whatever you plug into USB 3 have to be specifically USB 3 itself? Thanks.
I think USB 3 ports should be OK for USB 2 devices. They are supposed to
be backward compatible.

"Zaphod Beetlebrox" posted this useful URL:

http://www.usb3.com/usb3-info.html





--


James Silverton, Potomac

I'm "not"
(e-mail address removed)
 
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G

Gene E. Bloch

I have a Western Digital My Book Essentials 500Gn external USB hard drive. My
machine has an ASUS motherboard which has two USB 3 plugs in the back. Should I
see any increase in data transfer if I plug the hard drive into the USB plugs or
does whatever you plug into USB 3 have to be specifically USB 3 itself? Thanks.
USB 1 and 2 devices will operate at USB 1 and 2 speeds, as is to be
expected.
 
B

Brian Jackson

"Gene E. Bloch" wrote in message

I have a Western Digital My Book Essentials 500Gn external USB hard drive.
My
machine has an ASUS motherboard which has two USB 3 plugs in the back.
Should I
see any increase in data transfer if I plug the hard drive into the USB
plugs or
does whatever you plug into USB 3 have to be specifically USB 3 itself?
Thanks.
As previously stated, your data will transfer at a speed dictated by the
lowest type of USB on whatever your connecting ........ ie regardless of
your computer having USB 3, if your hard drive is only USB 2 you will not
see or benefit from any increased data transfer speed.
 
P

Paul

Brian said:
"Gene E. Bloch" wrote in message



As previously stated, your data will transfer at a speed dictated by the
lowest type of USB on whatever your connecting ........ ie regardless of
your computer having USB 3, if your hard drive is only USB 2 you will
not see or benefit from any increased data transfer speed.
I'd agree with the general drift of the answers received so far.

The USB3 jack on the computer, has two sets of contacts, and
allows pure USB3 devices, or older USB2/USB1.1 devices to be
plugged in.

If the external device is just a USB2 device, then it can't run
faster than its USB2 wiring and chip interface.

That being said, the *driver* installed for the USB3 chip,
may include a new protocol for transfer. I understand the
transfer rate of using the new protocol, may be an improvement
over what is normally used. So while the wire can't go any
faster than it could when plugged into a regular USB2
port, the software stack you end up with, could be
slightly different and more efficient.

For example, look at the table on this page. It claims something
called BOT protocol, gives 37MB/sec across a USB2 link. And
the UAS protocol, gives 40MB/sec. I don't know any more about it
than that. Maybe the documentation or README files that come with
the NEC drivers, say more on the subject ?

http://www.nordichardware.com/index.php?option=com_content&catid=112&lang=en&view=article&id=20792

Paul
 
G

Gene E. Bloch

"Gene E. Bloch" wrote in message
news:i3k9psmofmow.17cmhyu7u98tt$.dlg@40tude.net...
Here's what I said in that post:

"USB 1 and 2 devices will operate at USB 1 and 2 speeds, as is to be
expected."
 
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B

Brian Gregory [UK]

I have a Western Digital My Book Essentials 500Gn external USB hard drive.
My
machine has an ASUS motherboard which has two USB 3 plugs in the back.
Should I
see any increase in data transfer if I plug the hard drive into the USB
plugs or
does whatever you plug into USB 3 have to be specifically USB 3 itself?
Thanks.
Yes you need a USB3 device to take advantage of the USB3 speeds.

You might see some slight variation in speed in the situation you describe
but as far as I know its just the same as you might see with two different
USB2 ports which might perform slightly differently if they use different
types of interface chips. (say a USB2 port on your motherboard vs one on a
PCI expansion card that you have added)
 
O

occam

I think USB 3 ports should be OK for USB 2 devices. They are supposed to
be backward compatible.
Backward compatible - yes. Faster, no. With only USB3 <> USB3 can you
expect the transfer speeds specified.
 
O

occam

I think USB 3 ports should be OK for USB 2 devices. They are supposed to
be backward compatible.
Backward compatible - yes. Faster, no. With only USB3 <> USB3 can you
expect the increased transfer speeds specified.
 
R

rfdjr1

I have a Western Digital My Book Essentials 500Gn external USB hard drive. My
machine has an ASUS motherboard which has two USB 3 plugs in the back. Should I
see any increase in data transfer if I plug the hard drive into the USB plugs or
does whatever you plug into USB 3 have to be specifically USB 3 itself? Thanks.
Thanks for the replies. Probably should have done before I posted, but I checked
and there are, in fact, USB 3.0 external hard drives, so I'll probably just pick
up one since the prices are so low these days.
 
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P

Paul

Thanks for the replies. Probably should have done before I posted, but I checked
and there are, in fact, USB 3.0 external hard drives, so I'll probably just pick
up one since the prices are so low these days.
Expect a best case, with USB3 to USB3 hard drive enclosure, of around 130MB/sec.
That number is the disk head sustained transfer rate, so if you run HDTune 2.55 on
your new purchase, and the drive is of the current 7200RPM generation,
you should see somewhere around 130MB/sec. You'd see roughly the same
with an ESATA cable.

If you bought the very best SATA3 SSD (announced but perhaps not shipping yet),
and there was such a thing as a SATA3 enclosure with USB3, then you'd get over
300MB/sec sustained. It's possible available USB3 enclosures are still using
SATA2, in which case the SATA2 interface would be the limitation (as long
as the SSD is a SATA3 with transfer rates well above SATA2). The last benchmark
I've seen, from a USB3 disk enclosure, gave around 200MB/sec to an SSD. We're
still waiting for better enclosure chips to show up, to be able to see the
300MB/sec type numbers. To get above the 130MB/sec number, either requires
a RAID array in the enclosure, or a pretty good SATA SSD. One company has
designed an enclosure with RAID in it, but I don't know when that will ship.

Paul
 

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