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USB 2.0 external drive transfer speeds - confused !!

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July 10, 2004 10:14:05 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Is there anyone that can help me understand whether my external USB 2.0
drive is transferring at the correct speed. At first I thought that it
was only transferring at 1.1 speeds but I think I mixed up Mbit and
Mbyte speeds.

Anyway, using SiSoft Sandra reports a transfer speed of:

11,036 kB/s

At first I thought this must only be operating at USB 1.1 speed but then
I notcied that the Sandra program had a reference benchmark of 11,610
KB/s for a Hi-Speed USB ATA 100 drive. I am using a Maxtor 200Gb ATA
133 drive so now I am confused as to whether this is operating at USB
2.0 which I thought was 480 Mbit/s which = 60 MB/s ??

Help please !
Anonymous
a b G Storage
July 11, 2004 3:04:14 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

On Sat, 10 Jul 2004 18:14:05 GMT, Ian <ian@no-spam.com> wrote:

>At first I thought this must only be operating at USB 1.1 speed but then
>I notcied that the Sandra program had a reference benchmark of 11,610
>KB/s for a Hi-Speed USB ATA 100 drive. I am using a Maxtor 200Gb ATA
>133 drive so now I am confused as to whether this is operating at USB
>2.0 which I thought was 480 Mbit/s which = 60 MB/s ??

Tht sounds about right. USB speed are measured in Mbit, which is 8
times Mbytes. So 480 Mbit is 60M byte, 12 Mbit (USB 1.1) = 1.5 Mbyte
and the original USB specs: 1.5 (IIRC) Mbit which is 187.5 Kbyte

ATA speed are measured in Mbyte so ATA66 are about 66 Mbyte/sec.
Confusing? Consider unless you have hard drive capable of 10K RPM,
most hard drive can't read or write fast enough to take full advantage
of ATA100/133 and generally maxes out at 50Mbyte/sec and that's just
the burst rate. Sustained rate is a lot lower.

PS as long as we're talking about USB drives, I'd still suggest
firewire drive. Even though Firewire is slightly slower than USB2
(400 Mb vs 480 MB), Firewire can handle more traffic on the system
while USB is more of one-at-a-time thing. If you have USB drives, USB
modem, USB ethernet, USB mouse, USB game controller, etc, the USB
system would be very busy and the the speed of USB drive would
degrade.
--
To reply, replace digi.mon with tds.net
July 11, 2004 2:44:22 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

On Sat, 10 Jul 2004 23:04:14 -0400, Impmon <impmon@digi.mon> wrote:

>On Sat, 10 Jul 2004 18:14:05 GMT, Ian <ian@no-spam.com> wrote:
>
>>At first I thought this must only be operating at USB 1.1 speed but then
>>I notcied that the Sandra program had a reference benchmark of 11,610
>>KB/s for a Hi-Speed USB ATA 100 drive. I am using a Maxtor 200Gb ATA
>>133 drive so now I am confused as to whether this is operating at USB
>>2.0 which I thought was 480 Mbit/s which = 60 MB/s ??
>
>Tht sounds about right. USB speed are measured in Mbit, which is 8
>times Mbytes. So 480 Mbit is 60M byte, 12 Mbit (USB 1.1) = 1.5 Mbyte
>and the original USB specs: 1.5 (IIRC) Mbit which is 187.5 Kbyte


Thanks for replying to my message but I'm still unclear about whether my
external USB drive is performing as expected for a USB 2.0 connection.
The reported speed of the drive is 11,036 kB/s which doesn't seem to
match up with any of the documented USB standards ???
Related resources
Anonymous
a b G Storage
July 11, 2004 8:56:25 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

I believe max through put for USB 2.0 is 12 MBs (or 12,000 kBs)
and USB 1.1 max's around 1.5MBs
where as ATA100 and ATA133 is around 50-60MBs.
so it sound like your system is normal.

"Ian" <ian@no-spam.com> wrote in message
news:ka80f0lt95f95afn9l8bdlkgfoh6erhj9d@4ax.com...
>
> Is there anyone that can help me understand whether my external USB 2.0
> drive is transferring at the correct speed. At first I thought that it
> was only transferring at 1.1 speeds but I think I mixed up Mbit and
> Mbyte speeds.
>
> Anyway, using SiSoft Sandra reports a transfer speed of:
>
> 11,036 kB/s
>
> At first I thought this must only be operating at USB 1.1 speed but then
> I notcied that the Sandra program had a reference benchmark of 11,610
> KB/s for a Hi-Speed USB ATA 100 drive. I am using a Maxtor 200Gb ATA
> 133 drive so now I am confused as to whether this is operating at USB
> 2.0 which I thought was 480 Mbit/s which = 60 MB/s ??
>
> Help please !
>
>
>
July 12, 2004 2:35:49 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

On Sun, 11 Jul 2004 16:56:25 GMT, "Tod" <no_spam_me@comcast.net> wrote:

>I believe max through put for USB 2.0 is 12 MBs (or 12,000 kBs)
>and USB 1.1 max's around 1.5MBs
>where as ATA100 and ATA133 is around 50-60MBs.
>so it sound like your system is normal.

Thanks Tod. At least I know it's working as it's supposed to. Although
it seems a long way off 480Mbit/s.



>
>"Ian" <ian@no-spam.com> wrote in message
>news:ka80f0lt95f95afn9l8bdlkgfoh6erhj9d@4ax.com...
>>
>> Is there anyone that can help me understand whether my external USB 2.0
>> drive is transferring at the correct speed. At first I thought that it
>> was only transferring at 1.1 speeds but I think I mixed up Mbit and
>> Mbyte speeds.
>>
>> Anyway, using SiSoft Sandra reports a transfer speed of:
>>
>> 11,036 kB/s
>>
>> At first I thought this must only be operating at USB 1.1 speed but then
>> I notcied that the Sandra program had a reference benchmark of 11,610
>> KB/s for a Hi-Speed USB ATA 100 drive. I am using a Maxtor 200Gb ATA
>> 133 drive so now I am confused as to whether this is operating at USB
>> 2.0 which I thought was 480 Mbit/s which = 60 MB/s ??
>>
>> Help please !
>>
>>
>>
>
Anonymous
a b G Storage
July 12, 2004 3:41:17 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

I should have said "practical" through put for USB 2.0 is about 12MBs.

"Ian" <ian@no-spam.com> wrote in message
news:0kc3f019d283271vm3frmqt1hvpr7lrle5@4ax.com...
> On Sun, 11 Jul 2004 16:56:25 GMT, "Tod" <no_spam_me@comcast.net> wrote:
>
> >I believe max through put for USB 2.0 is 12 MBs (or 12,000 kBs)
> >and USB 1.1 max's around 1.5MBs
> >where as ATA100 and ATA133 is around 50-60MBs.
> >so it sound like your system is normal.
>
> Thanks Tod. At least I know it's working as it's supposed to. Although
> it seems a long way off 480Mbit/s.
>
>
>
> >
> >"Ian" <ian@no-spam.com> wrote in message
> >news:ka80f0lt95f95afn9l8bdlkgfoh6erhj9d@4ax.com...
> >>
> >> Is there anyone that can help me understand whether my external USB 2.0
> >> drive is transferring at the correct speed. At first I thought that it
> >> was only transferring at 1.1 speeds but I think I mixed up Mbit and
> >> Mbyte speeds.
> >>
> >> Anyway, using SiSoft Sandra reports a transfer speed of:
> >>
> >> 11,036 kB/s
> >>
> >> At first I thought this must only be operating at USB 1.1 speed but
then
> >> I notcied that the Sandra program had a reference benchmark of 11,610
> >> KB/s for a Hi-Speed USB ATA 100 drive. I am using a Maxtor 200Gb ATA
> >> 133 drive so now I am confused as to whether this is operating at USB
> >> 2.0 which I thought was 480 Mbit/s which = 60 MB/s ??
> >>
> >> Help please !
> >>
> >>
> >>
> >
>
Anonymous
a b G Storage
July 12, 2004 3:41:18 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Nonsense.

"Tod" <no_spam_me@comcast.net> wrote in message
news:wekIc.53868$JR4.10682@attbi_s54...
> I should have said "practical" through put for USB 2.0 is about 12MBs.
>
Anonymous
a b G Storage
July 12, 2004 4:24:24 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"Ian" <ian@no-spam.com> wrote in message news:8p22f0d2v85lvrrdpqihiunud2b4eps34a@4ax.com...
> On Sat, 10 Jul 2004 23:04:14 -0400, Impmon <impmon@digi.mon> wrote:
>
> >On Sat, 10 Jul 2004 18:14:05 GMT, Ian <ian@no-spam.com> wrote:
> >
> >> At first I thought this must only be operating at USB 1.1 speed but then
> >> I notcied that the Sandra program had a reference benchmark of 11,610
> >> KB/s for a Hi-Speed USB ATA 100 drive. I am using a Maxtor 200Gb
> >> ATA 133 drive so now I am confused as to whether this is operating at
> >> USB 2.0 which I thought was 480 Mbit/s which = 60 MB/s ??

Now why should a mere 33% increase in ATA bus speed lead to a 500%
increase in benchmark result? Do you have all your marbles in a row?

> >
> > That sounds about right.

> > USB speed are measured in Mbit,

No, they are not.

> > which is 8 times Mbytes.

Nope.
First there is serial protocol overhead and next there is command overhead.

> So 480 Mbit is 60M byte, 12 Mbit (USB 1.1) = 1.5 Mbyte
> >and the original USB specs: 1.5 (IIRC) Mbit which is 187.5 Kbyte

So all false.

>
>
> Thanks for replying to my message but I'm still unclear about whether my
> external USB drive is performing as expected for a USB 2.0 connection.
> The reported speed of the drive is 11,036 kB/s which doesn't seem to
> match up with any of the documented USB standards ???

That is because you snipped the part of his post that tried to deal with that
but you didn't bother reading it first.

And since when do IDE drive benchmarks ever
"match up with any of the documented IDE standards"?

>
>
>
Anonymous
a b G Storage
July 12, 2004 4:35:23 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

On Sun, 11 Jul 2004 10:44:22 GMT, Ian <ian@no-spam.com> wrote:

>Thanks for replying to my message but I'm still unclear about whether my
>external USB drive is performing as expected for a USB 2.0 connection.
>The reported speed of the drive is 11,036 kB/s which doesn't seem to
>match up with any of the documented USB standards ???

Not all hard drive can operate at full speed. Some of the higher
speed is usually only in burst speed and sustained speed is usually
lower.

Another possibility is you have other USB devices (modem, network,
etc) that is also communicating with the PC at the same time. The USB
can only handle so much traffic.
--
To reply, replace digi.mon with tds.net
Anonymous
a b G Storage
July 13, 2004 5:14:29 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"Impmon" <impmon@digi.mon> wrote in message news:1bf5f05dj78coi3bki76kvd971nmc673ru@4ax.com...
> On Sun, 11 Jul 2004 10:44:22 GMT, Ian <ian@no-spam.com> wrote:
>
> > Thanks for replying to my message but I'm still unclear about whether my
> > external USB drive is performing as expected for a USB 2.0 connection.
> > The reported speed of the drive is 11,036 kB/s which doesn't seem to
> > match up with any of the documented USB standards ???
>

> Not all hard drive can operate at full speed.

*No* drive will operate (sustained) at bus-speed.
In theory burst speed should be bus-speed but the benchmarks measure
the cachebuffer to interface speed and that excludes command overhead.

> Some of the higher speed is usually only in burst speed and sustained
> speed is usually lower.
>
> Another possibility is you have other USB devices (modem, network,
> etc) that is also communicating with the PC at the same time. The USB
> can only handle so much traffic.
> --
> To reply, replace digi.mon with tds.net
!