USB Hard Drive

  • Thread starter Thread starter A.M
  • Start date Start date
A

A.M

Hi,

I have a 10,000 RPM HDD attached to my computer by using USB port. Do I
loose any HDD speed?
Is IDE HDD faster than USB HDDs?

Thanks,
Alan
 
Thank Treeman for the information.

Do you know any place that shows speed benchmarks for USB HDDs, USB Keys and
IDE HDDs?

Thank you again,
Alan
 
Most (if not all) USB hard drives are simply IDE hard drives inside an
enclosure. The enclosure has a little pcb inside with a usb interface on one
end, and an IDE cable on the other. Pop an old one open some day and you
will see that you can put any IDE drive in an enclosure. They even sell bare
enclosures at compusa now.

The max speed of the USB 2.0 interface is 480 megabits/sec (or 60
megabytes/sec) I don't know of any single disk systems that can maintain a
sustained transfer of 60 megabytes per second. To get that kind of speed,
you usually have to have a striped array.

HD Tach is a great measurement tool.
http://www.simplisoftware.com/Public/index.php?request=HdTach
 
Thank you Rube.

I used the tool that you recommanded and it shows significant difference!
My SATA 160 GIG 7200 RPM HDD is almost 10 time faster than my 20 GIG 4200
RPM HDD plugged through USB.

Thanks again,
Alan
 
Rube said:
Most (if not all) USB hard drives are simply IDE hard drives inside an
enclosure. The enclosure has a little pcb inside with a usb interface on
one
end, and an IDE cable on the other. Pop an old one open some day and you
will see that you can put any IDE drive in an enclosure. They even sell
bare
enclosures at compusa now.

The max speed of the USB 2.0 interface is 480 megabits/sec (or 60
megabytes/sec) I don't know of any single disk systems that can maintain a
sustained transfer of 60 megabytes per second. To get that kind of speed,
you usually have to have a striped array.

HD Tach is a great measurement tool.
http://www.simplisoftware.com/Public/index.php?request=HdTach
Click to expand...


Alan:
It is true that if you measure the speed performance of a IDE HD in its USB
enclosure and that same HD mounted as an internal HD, you'll generally find
little if any difference as measured by HD Tach or similar drive speed
measuring tool.

However, there is a *considerable* speed performance difference, i.e., data
transfer rate, in a "real-life" scenario. For example, using a disk imaging
program such as Ghost or Acronis True Image to clone the contents of one's
internal HD to a USB 2.0 external HD, you'll get typical data transfer
speeds along the lines of 450 MB/min to 800 MB/min (using a medium-power
processor). Bear in mind we're talking about megabytes per minute. Data
transfer rates between two internal HDs in this scenario would be roughly
800 MB/min to 1.5 GB per/min.

So if you're using a USB 2.0 EHD that will be receiving or transmitting
relatively massive amounts of data, such as in the situation detailed above,
there is a decided performance "hit" using a USB EHD. On the other hand, if
you're primarily using the USB 2.0 EHD as a backup device for copying/moving
a relatively small amount of data between it and an internal HD, the
difference in actual transfer time is negligible - nothing to be really
concerned about. It's only when you're routinely receiving and transmitting
gigabytes of data between the internal HD and the USB 2.0 EHD that the speed
difference between the devices becomes truly meaningful.

All that I've said relates to 7200 rpm drives. I haven't worked with the
10,000 rpm drives in a USB EHD enclosure so it's entirely likely the data
transfer rate would be higher with that device.
Anna
 
Back
Top