USB 2 Transfer Speeds

Discussion in 'NZ Computing' started by Tony, Jun 20, 2005.

  1. Tony

    Tony Guest

    Well as I though USB 2 can be Slow


    "The modern USB 2.0 port supports three specific transfer speeds:

    A "low speed" USB device transfers data at 1.5 megabits per second.
    A "full speed" USB device transfers data at 12 megabits per second.
    A "high speed" USB device transfers data at 480 megabits per second.
    Unfortunately, a buyer has to be careful of the terminology. Technically, USB
    2.0 is a specification of the physical and electrical interface specification.
    A few vendors claim to have USB 2.0 ports but do not support high speed
    devices. So make sure that a device claims "high speed" or 480 Mb's before
    buying it."



    The other thing is how much of a CPU hog is it and its interrupt priority..

    I think that Firewire IEEE 1394 is a Far better HS interface..
    Tony, Jun 20, 2005
    #1
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  2. Tony

    MarkH Guest

    Tony <> wrote in
    news::

    >
    >
    >
    > Well as I though USB 2 can be Slow
    >
    >
    > "The modern USB 2.0 port supports three specific transfer speeds:
    >
    > A "low speed" USB device transfers data at 1.5 megabits per second.
    > A "full speed" USB device transfers data at 12 megabits per second.
    > A "high speed" USB device transfers data at 480 megabits per second.
    > Unfortunately, a buyer has to be careful of the terminology.
    > Technically, USB 2.0 is a specification of the physical and electrical
    > interface specification. A few vendors claim to have USB 2.0 ports but
    > do not support high speed devices. So make sure that a device claims
    > "high speed" or 480 Mb's before buying it."


    Interesting, or it was several years ago when this was new information.
    Now, over 98% of devices claiming USB2 are "high Speed". Mostly the
    slower devices like keyboards and mice are not claiming USB2 anyway.

    > The other thing is how much of a CPU hog is it and its interrupt
    > priority..


    USB is pretty good on the CPU usage.

    > I think that Firewire IEEE 1394 is a Far better HS interface..


    Well, it would be if that is the connection on the device that you are
    attaching to your computer. If you have a small flash memory device
    with a USB connection then USB2 is a far better interface (the plug will
    fit, for a start).

    In practical use USB2 High Speed (which is very common on HDD enclosures
    and flash memory drives) is very fast - I have managed to transfer at a
    rate of 1GB per minute to an old 20GB HDD in my USB2 enclosure. I own
    about a dozen devices that run at USB2 High speed and they are all as
    fast as you would expect.

    Firewire (IEEE 1394) is theoretically a little slower, but in practice
    it would equal or beat USB2. It would be unlikely to be much faster
    than USB2 though, most devices struggle to match the full speed of
    either interface anyway.

    For faster speed devices that have any chance of using it, the speed of
    Firewire 2 is pretty good at 800Mb/S.


    --
    Mark Heyes (New Zealand)
    See my pics at www.gigatech.co.nz (last updated 3-May-05)
    "There are 10 types of people, those that
    understand binary and those that don't"
    MarkH, Jun 20, 2005
    #2
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  3. Tony

    Richard Guest

    MarkH wrote:
    > Tony <> wrote in
    > news::
    >
    >
    >>
    >>
    >>Well as I though USB 2 can be Slow
    >>
    >>
    >>"The modern USB 2.0 port supports three specific transfer speeds:
    >>
    >>A "low speed" USB device transfers data at 1.5 megabits per second.
    >>A "full speed" USB device transfers data at 12 megabits per second.
    >>A "high speed" USB device transfers data at 480 megabits per second.
    >>Unfortunately, a buyer has to be careful of the terminology.
    >>Technically, USB 2.0 is a specification of the physical and electrical
    >>interface specification. A few vendors claim to have USB 2.0 ports but
    >>do not support high speed devices. So make sure that a device claims
    >>"high speed" or 480 Mb's before buying it."

    >
    >
    > Interesting, or it was several years ago when this was new information.
    > Now, over 98% of devices claiming USB2 are "high Speed". Mostly the
    > slower devices like keyboards and mice are not claiming USB2 anyway.
    >
    >
    >>The other thing is how much of a CPU hog is it and its interrupt
    >>priority..

    >
    >
    > USB is pretty good on the CPU usage.


    If by good you mean good at taking it all, then yeah

    HDD on USB here - 70-80% CPU - machine becomes sluggesh and unresponsive.

    HDD on 1394 - 20-30% CPU and machine still works fine.

    HDD on parallel ATA - 3% CPU and faster and machine uneffected

    This is all copying to a machine on the lan over 100baseT - the USB and firewire
    were not able to get the full 100meg by a long way (both peaked at about 60 and
    sat on about 40) whereas the parallel ata drive was sitting on about 95 megabit
    Richard, Jun 20, 2005
    #3
  4. Tony

    MarkH Guest

    Richard <> wrote in news::

    > MarkH wrote:
    >> Tony <> wrote
    >> in news::
    >>
    >>>The other thing is how much of a CPU hog is it and its interrupt
    >>>priority..

    >>
    >>
    >> USB is pretty good on the CPU usage.

    >
    > If by good you mean good at taking it all, then yeah


    By good I mean that it does not hog the CPU, hardly ever passing 30%.

    > HDD on USB here - 70-80% CPU - machine becomes sluggesh and
    > unresponsive.


    Have you thought about trying to download newer drivers or something? Or
    maybe replacing the computer, or using a PCI USB2 card?

    > HDD on 1394 - 20-30% CPU and machine still works fine.


    I have no trouble transferring a 700MB file from my USB2 2.5" enclosure
    with a 40GB 4200RPM laptop drive to my PC in less than a minute with the
    CPU usage on my 2.5 year old CPU not exceeding 35% and mostly between 15%
    and 25%. If I copy a file through the network to my USB2 HDD I can copy a
    500MB file in under a minute with the CPU usage at 20-30%.

    I have no problem typing this while testing my copy speed and CPU usage,
    with no noticeable difference in my PCs responsiveness.

    My PC is a P4-2.53 (533 bus) on an Asus P4PE M/B with 1GB of PC333 RAM.
    The USB controller on the M/Board is an Intel 82801DB/DBM USB 2.0 Enhanced
    Host Controller. The motherboard and CPU are now 2.5 years old and still
    performing very well.

    On my older PC it took 67 seconds to transfer a 700MB file (a little
    slower) and the CPU was fairly steady on 20-25%. That PC has a Intel 815
    chipset and a P3-866 CPU, the USB2 Controller is a NEC PCI card.

    Both machines are running WinXP Pro.


    --
    Mark Heyes (New Zealand)
    See my pics at www.gigatech.co.nz (last updated 3-May-05)
    "There are 10 types of people, those that
    understand binary and those that don't"
    MarkH, Jun 21, 2005
    #4
  5. Tony

    -=rjh=- Guest

    MarkH wrote:
    > Richard <> wrote in news::
    >
    >
    >>MarkH wrote:
    >>
    >>>Tony <> wrote
    >>>in news::
    >>>
    >>>
    >>>>The other thing is how much of a CPU hog is it and its interrupt
    >>>>priority..
    >>>
    >>>
    >>>USB is pretty good on the CPU usage.

    >>
    >>If by good you mean good at taking it all, then yeah

    >
    >
    > By good I mean that it does not hog the CPU, hardly ever passing 30%.
    >
    >
    >>HDD on USB here - 70-80% CPU - machine becomes sluggesh and
    >>unresponsive.

    >
    >
    > Have you thought about trying to download newer drivers or something? Or
    > maybe replacing the computer, or using a PCI USB2 card?
    >


    USB2.0 is fine here, too - my external USB drive gets transfer speeds
    about 2/3 of my onboard drive, and cpu usage is probably around 20%.
    This is a DSE PCI USB2.0 card, P3/667, WD external drive. PC is just as
    responsive as usual with large transfers taking place, for example
    continues playing mp3s with no interruption.

    I think Richard must have a hardware issue.
    -=rjh=-, Jun 21, 2005
    #5
  6. Tony

    Tim Guest

    Maybe you have a Via chipset?

    Regardless, I agree with MarkH - check you drivers, you should not have to
    suffer this.

    - Tim

    "Richard" <> wrote in message
    news:...
    > MarkH wrote:
    >> Tony <> wrote in
    >> news::
    >>>
    >>>
    >>>Well as I though USB 2 can be Slow
    >>>
    >>>
    >>>"The modern USB 2.0 port supports three specific transfer speeds:
    >>>
    >>>A "low speed" USB device transfers data at 1.5 megabits per second. A
    >>>"full speed" USB device transfers data at 12 megabits per second. A "high
    >>>speed" USB device transfers data at 480 megabits per second.
    >>>Unfortunately, a buyer has to be careful of the terminology.
    >>>Technically, USB 2.0 is a specification of the physical and electrical
    >>>interface specification. A few vendors claim to have USB 2.0 ports but
    >>>do not support high speed devices. So make sure that a device claims
    >>>"high speed" or 480 Mb's before buying it."

    >>
    >>
    >> Interesting, or it was several years ago when this was new information.
    >> Now, over 98% of devices claiming USB2 are "high Speed". Mostly the
    >> slower devices like keyboards and mice are not claiming USB2 anyway.
    >>
    >>
    >>>The other thing is how much of a CPU hog is it and its interrupt
    >>>priority..

    >>
    >>
    >> USB is pretty good on the CPU usage.

    >
    > If by good you mean good at taking it all, then yeah
    >
    > HDD on USB here - 70-80% CPU - machine becomes sluggesh and unresponsive.
    >
    > HDD on 1394 - 20-30% CPU and machine still works fine.
    >
    > HDD on parallel ATA - 3% CPU and faster and machine uneffected
    >
    > This is all copying to a machine on the lan over 100baseT - the USB and
    > firewire were not able to get the full 100meg by a long way (both peaked
    > at about 60 and sat on about 40) whereas the parallel ata drive was
    > sitting on about 95 megabit
    >
    Tim, Jun 21, 2005
    #6
  7. Tony

    Richard Guest

    Tim wrote:
    > Maybe you have a Via chipset?
    >
    > Regardless, I agree with MarkH - check you drivers, you should not have to
    > suffer this.


    USB is VIA on this machine, its an 845 chipset so only has usb1.1 in the chipset
    so they stuck a different controller on it.

    Similar thing happens on the 2 nforce2 machines, not tried one of the intel 875
    machines since I havent had a need to use it yet.
    Richard, Jun 21, 2005
    #7
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