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

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?
>>>

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