Re: [Thinkpad] X40 HD/USB very slow?

I'm guessing it's slow copying files to or from the internal drive. If
that internal drive is slow enough, it could be the bottleneck in the
transfer.

What is the sustained data rate on those 1.8" drives, anyway?

Chris

On Wed, 14 Nov 2007, Alex Austin wrote:

> From what I understand, this is about an external USB drive, which would
> only use DMA between the drive and the USB/IDE chip, and the setting of
> whether to use it or not is not exported to the computer.
>
> On Nov 14, 2007 8:56 AM, RWM <RWM@rwmann.com> wrote:
>
>> How about checking Device Mangler to see if the X20 HD ATA Controller
>> has inadvertently been set to (or defaulted to) a slow speed, such as
>> PIO Mode 0 (3.3) versus DMA-2 (16.7) or UDMA-6 (133).
>>
>>
>>
>> Scott Matthews wrote:
>>
>>> It's a Samsung drive in an Antec enclosure -- and it's perfectly fast on
>> the
>>> X61s.
>>>
>>> I think he was saying that his drive was only serving at 3.5MB/s -- and
>> so
>>> even though he had a potential of ~20MB/s vis USB2, it was limited to
>>> 3.5MB/s because of his drive.
>>>
>>> I'm not quite sure what to check, but it's definitely *much* slower on
>> the
>>> X20 than the X61s...
>>>
>>> Thanks, -Scott
>>>
>>>
>>>
>>>
>>>> I remember reading here that the T40 had an early and buggy
>> implementation
>>>> of USB 2.0, so it wouldn't surprise me if the X40 had the same.
>>>>
>>>> However, 3.5MiB/sec is much faster than USB1. USB 2.0 has a theoretical
>>>>
>>>>
>>> peak
>>>
>>>
>>>> speed of 55MiB/sec, but the command overhead in the USB stack and
>> storage
>>>> protocol makes it really closer to 20MiB/sec. Divide that by 40 (the
>> speed
>>>> multiplier from USB1/USB2) and you get 500KiB/sec.
>>>>
>>>> What model of USB drive is it? I'm wondering what the bandwidth of the
>>>> USB/IDE chip used is.
>>>>
>>>> On Nov 14, 2007 7:43 AM, Scott Matthews <scott@turnstyle.com> wrote:
>>>>
>>>>
>>>>
>>>>> Hi all, I just plugged a fast USB2 drive into my X40. I've used the
>> same
>>>>> drive on an X61s, and it was perfectly fast. But on the X40, it's very
>>>>> slow.
>>>>>
>>>>> A bit of Googling (http://forum.thinkpads.com/viewtopic.php?t=27910)
>> and
>>>>>
>>>>>
>>> I
>>>
>>>
>>>>> found somebody with the same problem, and he decided that the
>> bottleneck
>>>>> was
>>>>> his X40 drive -- at about 3.5MB/s (not much faster than USB1) as
>> opposed
>>>>> to
>>>>> about 25MB/s for USB2.
>>>>>
>>>>> Does anybody know if the X40 drive simply can't transfer data at a
>>>>> reasonable speed?
>>>>>
>>
>> --
>> R.W. Mann & Company, Inc. >> Airline Industry Analysis
>> Port Washington, NY 11050 >> tel 516-944-0900, fax -7280
>> mailto:info_at_RWMann.com >> URL http://www.RWMann.com/
>>
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Received on Wed Nov 14 11:48:30 2007