Opinicus said:
{Using WinXP (Home). All patches, updates, etc in place.}
I'm trying to copy a 12+ gigabyte folder containing 33 files from my
internal (slave) hard disk to a USB drive. It's going--barely--as I write.
The transfer speed varies wildly from as high as 25,039.0 kb/s to as low
as 649.0 kb/s. Typically the transfer starts out fast then slips and
lurches to a crawl, speeds up a little again, slows down, speeds up, etc,
etc, etc.
During the transfer slow-downs, my whole system seems to slow down as
well.
Turning off all other software doesn't improve matters nor does trying the
drive on a different port.
I've had similar problems in the past but never this serious.
The external drive is on a powered USB hub, to which no other devices are
attached at the moment.
What could be causing this behavior and how do I fix it?
Bob:
First of all, notwithstanding the issue you've raised, we'll assume that
your system functions without any other significant problem(s), speed-wise
or other, right?
While data transfer speeds involving USB external HDDs are not exactly
"speed demons" under any circumstances, your results are particularly
depressing. If my math is correct you're achieving data transfer speeds
involving those devices somewhere in the range of 40 MB/min to 147 MB/min.
(We prefer to use MB/min rather than kb/s when testing these data transfer
devices). In this connection I'm assuming those results you've cited are
"real-life" results, i.e., you've tested them manually and not relied on any
software timing device. We find many of the latter most unreliable.
Needless to say those are awfully slow speeds even for a USBEHD. Can we
assume the same speeds (roughly) are in play when data is moved or copied
from the USBEHD to the internal HDD?
And you've indicated that during these data-transfer episodes "my whole
system seems to slow down as well." While there might be some slowdown of
other operations at the time an enormous amount (such as your 12 GB worth of
data) is being copied, especially if these are other high-intensive
operations (audio/video manipulation, complex spreadsheet work, etc.), there
shouldn't be a terribly significant slowdown of other operations.
You mentioned you're using a "powered USB hub" re connecting the USBEHD. I'm
assuming the USBEHD has its own power supply. That being the case, have you
tried connecting the device directly to a USB port? Sometimes that has a
positive effect.
It's really hard to say what's going on here. Is there any chance of
removing the HDD from its USB enclosure and installing the drive in the
system as a secondary HDD and test it out under those circumstances to
determine if it's the HDD itself that's causing the problem? (And in the
process using a HDD diagnostic utility from the disk's manuf. to check out
the disk).
We've encountered so many unexplained problems affecting USBEHDs (involving
the USB 2.0 specification) over the years in an XP environment that nothing
surprises us any more. Although the problems usually relate to
non-recognition of the device and not the problem you're experiencing. It's
one of the reasons we're continually encouraging users (whenever practical)
to use an external HDD enclosure that provides SATA-to-SATA connectivity in
lieu of a USBEHD. There's a world of difference re data transfer speed and
their are other considerable advantages using this hardware as well.
Anyway, any chance on getting your hands on another USBEHD and compare the
two to determine if it's the device itself causing the problem? Do you use a
USB flash drive? How's its performance?
Anna
