Is SCSI faster than USB2?

  • Thread starter Thread starter John
  • Start date Start date
I have PIV 2.6 GHZ running XP Home and need to speed up my film
Click to expand...
scanner

Which film scanner? Was there one that had both SCSI and USB 2.0
capability? Some did have USB 1.1 and SCSI interfaces, but a USB 1.1
scanner on a USB 2.0 port is still a USB 1.1 scanner.

SCSI wont be faster than USB 2.0, either should allow the scanner to go
as fast as it can. Either will be faster than USB 1.1
 
John you Canon FS4000US does not have USB 2.0. It's USB1.1 and you
can confirm this at www.canonusa.com . Your computer may have USB 2.0
but your scanner can only transfer at the USB1.1 rate of about 12MB.

USB 1.1 12 Mbps
USB 2.0 480 Mbps
SCSI 40 Mbps

You will find a speed increase with SCSI. The scanner will run
smoother with less pausing in the middle of scans.
 
USB 1.1 12 Mbps
USB 2.0 480 Mbps
SCSI 40 Mbps
Click to expand...

Careful with numbers. First, SCSI can be much faster. Second, USB can
be much slower.

If only one device is hooked up on USB 2.0 the (still theoretical)
speed of 480 Mps is used only by this device, but the moment you chain
devices - or let one USB chip/driver control more than one device -
the speed will be shared. Faster devices can be slowed down, too, by
slower devices.

Consider FireWire, which, IIRC, is rated at 400 Mps. Now, if a scanner
offers both, USB 2.0 and FW, it should be a no-brainer to use USB,
shouldn't it? Well, with some scanners today, like my Minolta SE 5400,
you can test this. I found that FW is actually faster than USB, even
with only one device (the scanner) on the port.

And like SCSI FW offers its speed even with the highest possible
number of devices chained.

Another advantage of SCSI: the connection is safer regarding it
specifications and electronic noise. USB is more sensitive to
interferences.
 
Re: "...
And like SCSI FW offers its speed even with the highest possible
number of devices chained.
...."

First:
SCSI is a parallel 8-bit bus ... so a "40 MB" SCSI chain is running at 40 megaBYTES per
second ... roughly equivalent to 400 megaBITS per second.

Second:
Also don't forget ... SCSI has a 160 MByte variation that has been relatively common for
something like the last five (5) years. That's roughly equivalent to 1.6 Gbits per second.
[See ... for example ... the Adaptec SCSI Card 29160.]

There really *is* a reason that many very high end systems use SCSI!
 
Thanks to everyone - Wayne is right its USB1 so SCSI will be about 10x the
transfer rate. I was getting confused as my machine (Medion 8080) has USB2
but if the scanner is USB1 then thats of no use. So I've got a new SCSI
Adaptec 2940 off Ebay for £7.50 and all i need now is a suitably long HD 50
pin cable which will probably cost more than the card!!

I am thus far highly impressed with the scanner (FS4000US) which I bought
secondhand but looks and works like new. I have scanned a few slides and
negs in and in every case the scanner picks up the film grain before
pixellation becomes apparent & you can zoom and zoom into detail many times
before it gets lost in grain or pixellation. I understand neatimage can help
reduce grain effect & I have a lot of 'playing' to do before I get to the
best results.

The SCSI, I hope, will speed the scanner which is a bit slow on USB1.

Thanks for all your help.

john
 
Thanks to everyone - Wayne is right its USB1 so SCSI will be about 10x the
transfer rate.
Click to expand...

The bus may theoretically be that fast, but scanners are not that fast.
Still, the Canon 4000 will likely be 2x faster on SCSI (than USB 1.1).
 
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