A Computer hardware and components forum. ComputerBanter.com

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » ComputerBanter.com forum » General Hardware & Peripherals » Storage & Hardrives
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

USB 3.0 for a 2.5" drive?



 
 
Thread Tools Display Modes
  #1  
Old August 8th 15, 08:06 AM posted to comp.arch.storage
Charles T. Smith
external usenet poster
 
Posts: 3
Default USB 3.0 for a 2.5" drive?

Hi, a quick question for the experts.

I've gathered the impression that the interface technology (usb, sata,
pata) for disk drives is really irrelevant - for a single drive - because
disks can't deliver data fast enough to run into an interface bottleneck.

Maybe that assumption's not correct... anyway, I see an ad for a Seagate
external 2.5" drive which uses "USB 3.0 Super-speed, up to 10x faster
than USB 2.0". While that's likely true about USB 3.0, isn't it
cynically, unethically misleading about the effect on the drive's
performance? Or, why would Seagate supply drives with USB 3.0 technology?

I once did the numbers regarding cylinder, spin-rate, etc, but they say
that these days those parameters are irrelevant ...

cts
  #2  
Old August 8th 15, 09:01 AM posted to comp.arch.storage
Robert Wessel
external usenet poster
 
Posts: 11
Default USB 3.0 for a 2.5" drive?

On Sat, 8 Aug 2015 07:06:11 +0000 (UTC), "Charles T. Smith"
wrote:

Hi, a quick question for the experts.

I've gathered the impression that the interface technology (usb, sata,
pata) for disk drives is really irrelevant - for a single drive - because
disks can't deliver data fast enough to run into an interface bottleneck.

Maybe that assumption's not correct... anyway, I see an ad for a Seagate
external 2.5" drive which uses "USB 3.0 Super-speed, up to 10x faster
than USB 2.0". While that's likely true about USB 3.0, isn't it
cynically, unethically misleading about the effect on the drive's
performance? Or, why would Seagate supply drives with USB 3.0 technology?

I once did the numbers regarding cylinder, spin-rate, etc, but they say
that these days those parameters are irrelevant ...



They're not irrelevant. Modern desktop spinning disk can hit transfer
rates from the platter well over 100MB/s, at least for sequ3ential
reads. Enterprise drives are often in the 300MB/s range. USB2.0 is
limited to a theoretical 60MB/s, but as in practical terms rarely
achieves more than about half that. Also I/O to the cache onboard the
drives can happen faster than that. So USB 2.0 really is a bottle
neck when performing bulk (sequential) I/O to a disk drive. For
random I/O, it makes little difference.

Now as to whether or not USB 3.0 is *really* ten times faster is a
different question (sure, the interface is ~10 times faster), but
there's no doubt that things like backups to an external drive can run
considerably faster with a USB 3.0 connection in many cases. Backups
are a major use case for external drives, so sequential performance
*is* important.

OTOH, the practical difference between SATA 1/2/3 and USB 3.0 is
fairly minor. OTTH, the difference between SATA 1 and SATA 3 is only
a factor of four, and SATA 1 is 150MB/s anyway, far faster than USB
2.0 (and SATA tends to use more of its theoretical bandwidth).
Likewise the fastest PATA (133MB/s) interfaces have not been too far
off keeping up with desktop drives until recently.

In a sense the practical difference between PATA-133, SATA-1/2/3 and
USB 3.0 are modest, but USB 2.0 (or say PATA-33) is actually
substantially slower.
  #3  
Old August 8th 15, 09:05 AM posted to comp.arch.storage
Robert Wessel
external usenet poster
 
Posts: 11
Default USB 3.0 for a 2.5" drive?

On Sat, 08 Aug 2015 03:01:07 -0500, Robert Wessel
wrote:

On Sat, 8 Aug 2015 07:06:11 +0000 (UTC), "Charles T. Smith"
wrote:

Hi, a quick question for the experts.

I've gathered the impression that the interface technology (usb, sata,
pata) for disk drives is really irrelevant - for a single drive - because
disks can't deliver data fast enough to run into an interface bottleneck.

Maybe that assumption's not correct... anyway, I see an ad for a Seagate
external 2.5" drive which uses "USB 3.0 Super-speed, up to 10x faster
than USB 2.0". While that's likely true about USB 3.0, isn't it
cynically, unethically misleading about the effect on the drive's
performance? Or, why would Seagate supply drives with USB 3.0 technology?

I once did the numbers regarding cylinder, spin-rate, etc, but they say
that these days those parameters are irrelevant ...



They're not irrelevant. Modern desktop spinning disk can hit transfer
rates from the platter well over 100MB/s, at least for sequ3ential
reads. Enterprise drives are often in the 300MB/s range. USB2.0 is
limited to a theoretical 60MB/s, but as in practical terms rarely
achieves more than about half that. Also I/O to the cache onboard the
drives can happen faster than that. So USB 2.0 really is a bottle
neck when performing bulk (sequential) I/O to a disk drive. For
random I/O, it makes little difference.

Now as to whether or not USB 3.0 is *really* ten times faster is a
different question (sure, the interface is ~10 times faster), but
there's no doubt that things like backups to an external drive can run
considerably faster with a USB 3.0 connection in many cases. Backups
are a major use case for external drives, so sequential performance
*is* important.

OTOH, the practical difference between SATA 1/2/3 and USB 3.0 is
fairly minor. OTTH, the difference between SATA 1 and SATA 3 is only
a factor of four, and SATA 1 is 150MB/s anyway, far faster than USB
2.0 (and SATA tends to use more of its theoretical bandwidth).
Likewise the fastest PATA (133MB/s) interfaces have not been too far
off keeping up with desktop drives until recently.

In a sense the practical difference between PATA-133, SATA-1/2/3 and
USB 3.0 are modest, but USB 2.0 (or say PATA-33) is actually
substantially slower.



And here's an on-point Macworld article from a few years ago:

http://www.macworld.com/article/2039...0-really-.html
  #4  
Old August 8th 15, 10:41 AM posted to comp.arch.storage
Richard Kettlewell
external usenet poster
 
Posts: 11
Default USB 3.0 for a 2.5" drive?

"Charles T. Smith" writes:
Hi, a quick question for the experts.

I've gathered the impression that the interface technology (usb, sata,
pata) for disk drives is really irrelevant - for a single drive - because
disks can't deliver data fast enough to run into an interface bottleneck.


USB2 is slow enough that it’s a serious bottleneck.

Maybe that assumption's not correct... anyway, I see an ad for a Seagate
external 2.5" drive which uses "USB 3.0 Super-speed, up to 10x faster
than USB 2.0". While that's likely true about USB 3.0, isn't it
cynically, unethically misleading about the effect on the drive's
performance? Or, why would Seagate supply drives with USB 3.0 technology?


USB3-connected drives are *much* faster than USB2, based on the drives I
have.

--
http://www.greenend.org.uk/rjk/
  #5  
Old August 9th 15, 09:19 PM posted to comp.arch.storage
Charles T. Smith
external usenet poster
 
Posts: 3
Default USB 3.0 for a 2.5" drive?

Thanks, gentlemen.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
External USB hard drive showing wrong "Free Space" "Used Space" inthe Capacity RayLopez99 Homebuilt PC's 3 February 17th 14 08:40 PM
USB bootable maker: Diff between "HP Drive Key Boot Utility" and "HP USB Disk Storage Format Tool"? Jason Stacy Storage (alt) 1 April 21st 09 01:14 AM
WinExplorer shows no "Used space/Free space" in properties for USB stick drive ? "Optimized for quick removal" error? Joe deAngelo Storage (alt) 0 January 18th 08 01:28 PM
How to get rid of "Please select the operating system to start", conflicts with Drive Image Mbr Storage (alt) 1 September 21st 07 07:56 PM
Norton Ghost 9.0 and new SATA drive "copy one drive to another" T. T. Homebuilt PC's 4 September 6th 06 07:25 AM


All times are GMT +1. The time now is 05:34 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright ©2004-2018 ComputerBanter.com.
The comments are property of their posters.