Subject: Re: usb 1.1 vs 2.0
From: Jim Gribbin (jgribbin@alaska.net)
Date: Tue Jan 07 2003 - 01:52:31 AKST
My scans were of a portion of a color slide. .91in X .91in X 3200 dpi.
My main issue is that I expected the connection speed to effect the
scanning speed. The scans I attempted were the same slide at the same
resolution on the same scanner with the same software on the same box.
The only change being the usb interface used.
I didn't expect a straight 40x change in scanning speed (the amount of
theoretical bandwidth change), but I did expect a significant increase.
My stopwatch says there is no difference. The 90 to 95 sec times that
you found for a negative implies 2x what I'm getting.
I'll put W98se on a spare drive in the next day or two and see if there
is a difference with SIIG and Epson's windoze drivers. It would be
interesting to try a mobo with usb 2.0 built in as well.
I have run across information in researching this that implies there are
very few devices actually capable of more than 20MB/sec in the real
world and that the chipset used by SIIG (NEC) has a bottleneck at about
28MB/sec, 160Mb/sec and 224Mb/sec respectively. The NEC chipset seems to
be the main one the the linux drivers are centered on.
480Mb/sec - Yeah-Right.
Jim Gribbin
On Mon, 2003-01-06 at 22:22, James Zuelow wrote:
> On 06 Jan 2003 19:09:49 -0900
> "Greg Madden" <pabi@gci.net> wrote:
>
> >
> > On Mon, 2003-01-06 at 17:22, James Zuelow wrote:
> > >
> > > On 05 Jan 2003 14:46:02 -0900
> > > "Jim Gribbin" <jgribbin@alaska.net> wrote:
> > >
>
> > I think you made the case for connection speed does affect scanning
> > speed :) A 8x10 photo scanned at 600dpi is about 82mb. A scanner
> > that sends this data to the computer on the fly will take the
> > connection speed divided by throughput to get time.I do think it may
> > depend on the scanner. In the case of a page of text it shouldn't
> > take three minutes unless the scanner scan mechanism takes three
> > minutes, most don't take three minutes to scan.
> > --
>
> I did a little google work and couldn't find a handy link for an Epson
> 2450 that measured both the time to scan an image and the size of the
> image. However it looks like the fastest negative scans take about
> 90-95 seconds at high resolution. If you're using the Firewire
> interface at 400Mb/s, that is a roughly 4.8GB image, and for USB 2.0
> is is only 2.4GB. So your max resolution is much higher than my old
> scanner can do. :)
>
> Cheers,
>
> James
>
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