bottleneck in scanning

  • Thread starter Thread starter Mike
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M

Mike

I've got an Epson 4990 scanner and Fireware add-on PCI card on the way.

How CPU-intensive is scanning? Where is the bottleneck?

I ask because I have an older Dell server machine with a SCSI RAID disk
array outfitted with 10,000 RPM disk drives. The I/O throughput of this
machine is very good, however the 2 CPUs are older 1.1GHz Pentium IIIs.

On the other hand, my desktop machine is a faster Athlon 2100 XP machine,
but the I/O isn't as good with a single 7200RPM IDE drive.

Any thoughts on which machine would be better for large scans? I plan on scanning 4x5" transparencies at 2400 and
4800DPI.

Does Photoshop utilize 2 CPUs for basic operations? If not, the Athlon
would certainly be faster for post-processing.
 
Mike said:
I've got an Epson 4990 scanner and Fireware add-on PCI card on the way.

How CPU-intensive is scanning? Where is the bottleneck?
Click to expand...
Not much on the host. The bottleneck is most likely the scanner, the bus
speed, and the disk drive speed.
I ask because I have an older Dell server machine with a SCSI RAID disk
array outfitted with 10,000 RPM disk drives. The I/O throughput of this
machine is very good, however the 2 CPUs are older 1.1GHz Pentium IIIs.
Click to expand...
Yes, 10,000 rpm disk drives are fast.
On the other hand, my desktop machine is a faster Athlon 2100 XP machine,
but the I/O isn't as good with a single 7200RPM IDE drive.
Click to expand...
7200 rpm drives aren't as fast.
Any thoughts on which machine would be better for large scans? I plan on
scanning 4x5" transparencies at 2400 and
4800DPI.
Click to expand...
The one with the fastest drives... Haven't you answered your own question?
Does Photoshop utilize 2 CPUs for basic operations? If not, the Athlon
would certainly be faster for post-processing.
Click to expand...
What does Adobe say about this issue?
Jim
 
Mike said:
I've got an Epson 4990 scanner and Fireware add-on PCI card on the way.

How CPU-intensive is scanning? Where is the bottleneck?

I ask because I have an older Dell server machine with a SCSI RAID disk
array outfitted with 10,000 RPM disk drives. The I/O throughput of this
machine is very good, however the 2 CPUs are older 1.1GHz Pentium IIIs.

On the other hand, my desktop machine is a faster Athlon 2100 XP machine,
but the I/O isn't as good with a single 7200RPM IDE drive.

Any thoughts on which machine would be better for large scans? I plan on
scanning 4x5" transparencies at 2400 and
4800DPI.

Does Photoshop utilize 2 CPUs for basic operations? If not, the Athlon
would certainly be faster for post-processing.
Click to expand...
The primary bottleneck is the scanner itself. A scanner is a mechanical
device with stepping motors that only step at a fixed rate. If the file
transfer interface (USB or firewire) is slow, then the scanner has to wait
for the file transfer.

That happens when you have too much resolution and too big an area to scan.

File size for 4"x5" at 2400 DPI in color is about 345.6 Megabytes. Double
the DPI and you increase file size four times. 4X5 at 4800 DPI creates a
1.3824 GB file.

If you can transfer 30 MB/Sec, your 345.6 Megabyte file transfer takes 11.52
seconds. (Practical file transfer for USB 2.0).

No way around physics.
 
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