USB hard disk speed?

When I recently copied about 4.6GB from my AcomData 7200RPM USB 2.0
60GB external disk drive to a Verbatim 16X DVD+R disk via my Plextor
PX-716A 16X internal drive, there were several pauses to replenish the
cache after it reached about 8X write speed. The copy operation
averaged about 400MB/minute. During verification, it paused again
several times after it reached about 8X read speed. I expected
something faster both directions. Copying the same data between from
an internal hard drive and the DVD drive results in no such pauses or
slowdowns, so I presume the USB 2.0 interface slows the operation.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Russell May

"Russell May" wrote in message
...
When I recently copied about 4.6GB from my AcomData 7200RPM USB 2.0
60GB external disk drive to a Verbatim 16X DVD+R disk via my Plextor
PX-716A 16X internal drive, there were several pauses to replenish the
cache after it reached about 8X write speed. The copy operation
averaged about 400MB/minute. During verification, it paused again
several times after it reached about 8X read speed. I expected
something faster both directions. Copying the same data between from
an internal hard drive and the DVD drive results in no such pauses or
slowdowns, so I presume the USB 2.0 interface slows the operation.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Russell May


Did you try to copy same data between internal HD and USB 2.0 HD?

On Mon, 29 Aug 2005 13:01:17 -0400, "Peter"
wrote:


"Russell May" wrote in message
.. .
When I recently copied about 4.6GB from my AcomData 7200RPM USB 2.0
60GB external disk drive to a Verbatim 16X DVD+R disk via my Plextor
PX-716A 16X internal drive, there were several pauses to replenish the
cache after it reached about 8X write speed. The copy operation
averaged about 400MB/minute. During verification, it paused again
several times after it reached about 8X read speed. I expected
something faster both directions. Copying the same data between from
an internal hard drive and the DVD drive results in no such pauses or
slowdowns, so I presume the USB 2.0 interface slows the operation.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Russell May


Did you try to copy same data between internal HD and USB 2.0 HD?

Reading and writing the USB 2.0 HD subjectively seems a little slow:
Sometimes there are a few pauses while playing video on the USB drive.
Copying between internal HD and USB HD is significantly slower than
copying between internal hard disks, but I have not timed it. I have
just lived with it being a little slow. The USB performance became
more important when I got a DVD drive and larger internal HD.

I did a little research and found this:
http://www.tomshardware.com/storage/20030116/

The review is a couple of years older than my USB drive but I think
the enclosure is from the same manufacturer. The review shows even
lower write performance than what I got while copying to DVD, but
significantly higher read performance.

My external drive also has a Firewire connection which might give
better performance. I have not tried it, but maybe I should do so.

"Russell May" wrote in message
...
On Mon, 29 Aug 2005 13:01:17 -0400, "Peter"
wrote:


"Russell May" wrote in message
. ..
When I recently copied about 4.6GB from my AcomData 7200RPM USB 2.0
60GB external disk drive to a Verbatim 16X DVD+R disk via my Plextor
PX-716A 16X internal drive, there were several pauses to replenish the
cache after it reached about 8X write speed. The copy operation
averaged about 400MB/minute. During verification, it paused again
several times after it reached about 8X read speed. I expected
something faster both directions. Copying the same data between from
an internal hard drive and the DVD drive results in no such pauses or
slowdowns, so I presume the USB 2.0 interface slows the operation.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Russell May


Did you try to copy same data between internal HD and USB 2.0 HD?

Reading and writing the USB 2.0 HD subjectively seems a little slow:
Sometimes there are a few pauses while playing video on the USB drive.
Copying between internal HD and USB HD is significantly slower than
copying between internal hard disks, but I have not timed it. I have
just lived with it being a little slow. The USB performance became
more important when I got a DVD drive and larger internal HD.

Russ - I find very little difference in copying from one internal harddrive
to another vs copying from an internal harddrive to a harddrive in a USB 2
enclosure.

Just to confirm, did you measure the copy from the internal harddrive to the
DVD?

Also, how are you 'copying' to a DVD drive? Using packet writing with an
RW?

I did a little research and found this:
http://www.tomshardware.com/storage/20030116/

The review is a couple of years older than my USB drive but I think
the enclosure is from the same manufacturer. The review shows even
lower write performance than what I got while copying to DVD, but
significantly higher read performance.

My external drive also has a Firewire connection which might give
better performance. I have not tried it, but maybe I should do so.

On Mon, 29 Aug 2005 23:10:13 GMT, "fj" wrote:


"Russell May" wrote in message
.. .
On Mon, 29 Aug 2005 13:01:17 -0400, "Peter"
wrote:


"Russell May" wrote in message
...
When I recently copied about 4.6GB from my AcomData 7200RPM USB 2.0
60GB external disk drive to a Verbatim 16X DVD+R disk via my Plextor
PX-716A 16X internal drive, there were several pauses to replenish the
cache after it reached about 8X write speed. The copy operation
averaged about 400MB/minute. During verification, it paused again
several times after it reached about 8X read speed. I expected
something faster both directions. Copying the same data between from
an internal hard drive and the DVD drive results in no such pauses or
slowdowns, so I presume the USB 2.0 interface slows the operation.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Russell May


Did you try to copy same data between internal HD and USB 2.0 HD?

Reading and writing the USB 2.0 HD subjectively seems a little slow:
Sometimes there are a few pauses while playing video on the USB drive.
Copying between internal HD and USB HD is significantly slower than
copying between internal hard disks, but I have not timed it. I have
just lived with it being a little slow. The USB performance became
more important when I got a DVD drive and larger internal HD.

Russ - I find very little difference in copying from one internal harddrive
to another vs copying from an internal harddrive to a harddrive in a USB 2
enclosure.

Just to confirm, did you measure the copy from the internal harddrive to the
DVD?

Also, how are you 'copying' to a DVD drive? Using packet writing with an
RW?

I did a little research and found this:
http://www.tomshardware.com/storage/20030116/

The review is a couple of years older than my USB drive but I think
the enclosure is from the same manufacturer. The review shows even
lower write performance than what I got while copying to DVD, but
significantly higher read performance.

My external drive also has a Firewire connection which might give
better performance. I have not tried it, but maybe I should do so.


I timed several operations. I used only Verbatim 16X DVD+R disks.

Data were written from HD to DVD via "Nero 6 Ulta Edition" Burning
ROM. Data were written from HD or DVD to HD using copy and paste in
"My Computer". Data written from internal HD to internal HD were
copied and pasted between directories on the same partition. Data
total 4460MB (4,704,600,604 bytes) from 31616 files and 1604 folders.

Environment: OS=WinXP Home SP2, CPU=P4 2.4GHz, Mbd=Gigabyte 8IEXP,
memory=1.0GB ECC DDR, internal HD=Samsung SP2014N (200GB NTFS 7200RPM
ATA100, indexing enabled), external HD=Samsung SP6003H (60GB NTFS
7200RPM ATA100 in Acom Data USB/FW enclosure, indexing disabled),
DVD drive=Plextor PX-716A (16X ATA66), media=Verbatim 16X DVD+R,
antivirus=CA eTrust, antispam=Microsoft, #tasks=about 48,
applications=none except My Computer or Nero as applicable.

Copy times and rates:
From DVD to internal HD: 26min 10sec (about 174MB/minute)
From internal HD to internal HD: 9min 48sec (about 455MB/minute)
From internal HD to USB 2.0 HD: 10min 5sec (about 442MB/minute)
From USB 2.0 HD to internal HD: 10min 14sec (about 435MB/minute)
From internal HD to DVD: write 7min 55sec (about 565MB/minute)
verify 7min 17sec (about 612MB/minute)
From USB 2.0 HD to DVD: write 10min 5sec (about 442MB/minute)
verify 7min 20sec (about 608MB/minute)

I did not have enough time to measure from DVD to USB 2.0 HD.

Disabling Microsoft AntiSpam had no significant effect.

Snoozing (disabling) CA eTrust Antivirus had a significant effect.
From internal HD to internal HD: 7min 1sec (about 637MB/minute)
about 40% faster than with AV.

Writing to DVD was irregular:
From internal HD to DVD: Write operation paused four times to
replenish the read buffer at about 2'58", 3'10", 3'35", 7'15". Verify
operation started at about 4.9X, paused starting at about 25% progress
and 6.8X, varied irregularly from 960KB/sec to 8X until about 50%
progress, became regular again, finished at 11.8X.
From USB 2.0 HD to DVD: Write operation paused fifteen times to
replenish the buffer starting at about 2'10". It paused about every 30
seconds. Verify operation started at about 4.9X, went to 7.3X at about
25% progress, varied irregularly from there to about 32% progress,
became regular to about 56%, varied again to about 68%, went to 10.7X
there and became regular until about 97% progress, finished at 11.3X.

Plextools Professional Write Transfer rate test results were irregular
DVD disk #1: Write Transfer rate started at 6.76X, went to about 14X
at 3.1GB, dropped to steady 12.23X there, dropped to
steady 4.07X at about 3.6GB, finished at 4.07X.
DVD disk #1: Simulated Write started at 6.76X, dropped to steady
12.23X at about 3.3GB, finished at 12.23X.
DVD disk #2: Write Transfer rate started at 6.76X, went to about 14.5X
at 3.6GB, dropped to steady 12.23X there, finished at
12.23X.
DVD disk #2: Simulated Write started at 6.76X, finished at 16.29X.

Plextools Professional Read Transfer rate test results were regular
for both DVDs: Read transfer rate started at 4.93X, ended at 11.81X.

Writing an image of the internal HD (about 27GB) to the USB 2.0 HD
using Ghost 2003 averages about 410MB/minute, fills up the USB HD.

Copy times and rates:
From internal HD to internal HD: 9min 48sec (about 455MB/minute)
From internal HD to USB 2.0 HD: 10min 5sec (about 442MB/minute)
From USB 2.0 HD to internal HD: 10min 14sec (about 435MB/minute)
From internal HD to DVD: write 7min 55sec (about 565MB/minute)
verify 7min 17sec (about 612MB/minute)
From USB 2.0 HD to DVD: write 10min 5sec (about 442MB/minute)
verify 7min 20sec (about 608MB/minute)

I did not have enough time to measure from DVD to USB 2.0 HD.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Data total 4460MB (4,704,600,604 bytes) from 31616 files and 1604 folders.

There is a pattern. Whenever USB 2.0 HD is involved in data copy, best speed
drops 8 min range to 10 min range. I'm assuming that USB 2.0 HD is slower
than internal HD, more fragmented or USB 2.0 has higher overhead for
transferring that many (30K+) files.

When you say "from internal HD to internal HD" do you mean the same HD or
two different internal HDs?

"Peter" wrote in message
Copy times and rates:
From internal HD to internal HD: 9min 48sec (about 455MB/minute)
From internal HD to USB 2.0 HD: 10min 5sec (about 442MB/minute)
From USB 2.0 HD to internal HD: 10min 14sec (about 435MB/minute)
From internal HD to DVD: write 7min 55sec (about 565MB/minute)
verify 7min 17sec (about 612MB/minute)
From USB 2.0 HD to DVD: write 10min 5sec (about 442MB/minute)
verify 7min 20sec (about 608MB/minute)

I did not have enough time to measure from DVD to USB 2.0 HD.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Data total 4460MB (4,704,600,604 bytes) from 31616 files and 1604 folders.

There is a pattern. Whenever USB 2.0 HD is involved in data copy, best speed
drops 8 min range to 10 min range.

I'm assuming that USB 2.0 HD is slower than internal HD,

Now isn't that is a big surprise when USB-2 is limited to ~35MB/s.

more fragmented

Possibly, since the 435/60=~7MB/s is well below the 35MB/s USB limit.

or USB 2.0 has higher overhead for transferring that many (30K+) files.

That should be a bug in the OS then.


When you say "from internal HD to internal HD" do you mean the same HD or
two different internal HDs?

On Tue, 30 Aug 2005 10:39:32 -0400, "Peter"
wrote:

Copy times and rates:
From internal HD to internal HD: 9min 48sec (about 455MB/minute)
From internal HD to USB 2.0 HD: 10min 5sec (about 442MB/minute)
From USB 2.0 HD to internal HD: 10min 14sec (about 435MB/minute)
From internal HD to DVD: write 7min 55sec (about 565MB/minute)
verify 7min 17sec (about 612MB/minute)
From USB 2.0 HD to DVD: write 10min 5sec (about 442MB/minute)
verify 7min 20sec (about 608MB/minute)

I did not have enough time to measure from DVD to USB 2.0 HD.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Data total 4460MB (4,704,600,604 bytes) from 31616 files and 1604 folders.

There is a pattern. Whenever USB 2.0 HD is involved in data copy, best speed
drops 8 min range to 10 min range. I'm assuming that USB 2.0 HD is slower
than internal HD, more fragmented or USB 2.0 has higher overhead for
transferring that many (30K+) files.

When you say "from internal HD to internal HD" do you mean the same HD or
two different internal HDs?


Same HD. "Data written from internal HD to internal HD were
copied and pasted between directories on the same partition."

On Tue, 30 Aug 2005 10:39:32 -0400, "Peter"
wrote:

Copy times and rates:
From internal HD to internal HD: 9min 48sec (about 455MB/minute)
From internal HD to USB 2.0 HD: 10min 5sec (about 442MB/minute)
From USB 2.0 HD to internal HD: 10min 14sec (about 435MB/minute)
From internal HD to DVD: write 7min 55sec (about 565MB/minute)
verify 7min 17sec (about 612MB/minute)
From USB 2.0 HD to DVD: write 10min 5sec (about 442MB/minute)
verify 7min 20sec (about 608MB/minute)

I did not have enough time to measure from DVD to USB 2.0 HD.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Data total 4460MB (4,704,600,604 bytes) from 31616 files and 1604 folders.

There is a pattern. Whenever USB 2.0 HD is involved in data copy, best speed
drops 8 min range to 10 min range. I'm assuming that USB 2.0 HD is slower
than internal HD, more fragmented or USB 2.0 has higher overhead for
transferring that many (30K+) files.

Copying between internal HD and USB drive was only about 20 seconds
slower (about 3%) than copying from internal HD to internal HD, not
two minutes. The two minute difference between the HDs' times was for
writing to the DVD drive. See above.

Both HDs were defragmented prior to the tests.

The SP6003H is slower than the SP2014N, but both should be capable of
sustained transfer rates well over 657MB/minute (11MB/second).

USB overhead might be significant if the USB enclosure operates like
to the one reviewed by tomshardware, mentioned in my previous-previous
message. The review is about the same age as my USB drive, not two
years older as I said in that message.

OS or seek time overhead seems much more than I expected.

Antivirus had more effect than I expected. Copying without AV
"From internal HD to internal HD: 7min 1sec (about 637MB/minute)
about 40% faster than with AV."

I tried the internal HD to to internal HD test on a different computer
(Dell GX260, OS=Win2K SP4, CPU=P4 2.4GHz, HD=IBM 30GB 75GXP NTFS) and
data (3,278,976,512 bytes; 47552 files; 2119 folders). Disabling
Symantec Antivirus File System Auto-Protect sped it up by about 25%
(16min 58sec versus 21min 8sec).

Copying from the DVD seems slow
"From DVD to internal HD: 26min 10sec (about 174MB/minute)".

Writing to the DVD was irregular and sometimes slow (results deleted
above). I don't have easy access to another computer with a DVD drive.

These tests make me begin to wonder whether there is a problem with
the DVD drive. It's about six weeks old, with the latest firmware.

The media could be bad, but Plextor recommends these Verbatim 16X
DVD+R disks and cdrlabs tested them to be among the best for this
drive.

When you say "from internal HD to internal HD" do you mean the same HD or
two different internal HDs?


Same HD. "Data written from internal HD to internal HD were
copied and pasted between directories on the same partition."

On Tue, 30 Aug 2005 19:06:35 +0200, "Folkert Rienstra"
wrote:

"Peter" wrote in message
Copy times and rates:
From internal HD to internal HD: 9min 48sec (about 455MB/minute)
From internal HD to USB 2.0 HD: 10min 5sec (about 442MB/minute)
From USB 2.0 HD to internal HD: 10min 14sec (about 435MB/minute)
From internal HD to DVD: write 7min 55sec (about 565MB/minute)
verify 7min 17sec (about 612MB/minute)
From USB 2.0 HD to DVD: write 10min 5sec (about 442MB/minute)
verify 7min 20sec (about 608MB/minute)

I did not have enough time to measure from DVD to USB 2.0 HD.

Is 400MB/minute normal for copying between a USB 2.0 hard drive and
internal 16X DVD drive? Is there something simple to improve it?

Data total 4460MB (4,704,600,604 bytes) from 31616 files and 1604 folders.

There is a pattern. Whenever USB 2.0 HD is involved in data copy, best speed
drops 8 min range to 10 min range.

I'm assuming that USB 2.0 HD is slower than internal HD,

Now isn't that is a big surprise when USB-2 is limited to ~35MB/s.

more fragmented

Possibly, since the 435/60=~7MB/s is well below the 35MB/s USB limit.

or USB 2.0 has higher overhead for transferring that many (30K+) files.

That should be a bug in the OS then.


When you say "from internal HD to internal HD" do you mean the same HD or
two different internal HDs?

Both drives were defragmented before the tests.

I knew that USB 2.0 is limited to less than its maximum data rate of
60MB/sec, but I did not how much less. Thanks for the information.