The drive is a Western Digital 120 GB special edition (WD1200JB).
While installing XP, I formatted the entire drive as a single NTFS
partition (using the slow format to be sure and check for any surface
errors). There were no bad sectors found during format. I then
proceeded to test transfer rates from the drive. One of these tests
involved creating several large files in XP and then reading them in
as fast as possible. While testing one of these files (a 40 GB file),
everything was humming along fine (47 MB/s transfer from the drive)
until reaching a certain segment of the file (probably around 15 GB in
size). In that segment, throughput dropped to around 1-3 MB/s. After
passing the segment, transfer rates increased again. I performed the
test a couple more times and verified that the same segment was
reading slower. I then did a sequential read of the drive at a lower
level, and it appears there are parts of the drive that just read
slowly, dropping from 50-27MB/s down to 3-1MB/s. I never got any IO
errors while performing any of these tests.
My question is this: does anyone know why a drive would have large
regions that read 10 times (or more) slower than other regions? I'm
really hoping the answer is not that the hard drive is dying and that
it is having to work hard at reading almost faulty sectors.

Thanks,
Anodos

On 18 Dec 2003 07:47:23 -0800, (E-Mail Removed) (anodos) wrote:

>The drive is a Western Digital 120 GB special edition (WD1200JB).
>While installing XP, I formatted the entire drive as a single NTFS
>partition (using the slow format to be sure and check for any surface
>errors). There were no bad sectors found during format. I then
>proceeded to test transfer rates from the drive. One of these tests
>involved creating several large files in XP and then reading them in
>as fast as possible. While testing one of these files (a 40 GB file),
>everything was humming along fine (47 MB/s transfer from the drive)
>until reaching a certain segment of the file (probably around 15 GB in
>size). In that segment, throughput dropped to around 1-3 MB/s. After
>passing the segment, transfer rates increased again. I performed the
>test a couple more times and verified that the same segment was
>reading slower. I then did a sequential read of the drive at a lower
>level, and it appears there are parts of the drive that just read
>slowly, dropping from 50-27MB/s down to 3-1MB/s. I never got any IO
>errors while performing any of these tests.
>My question is this: does anyone know why a drive would have large
>regions that read 10 times (or more) slower than other regions? I'm
>really hoping the answer is not that the hard drive is dying and that
>it is having to work hard at reading almost faulty sectors.
>
>Thanks,
> Anodos

The drive probably has a few bad sectors here and there, like most,
and has to go to the spare sectors allocated for this purpose. of
course that's a big performance drop. Another possibility is that as
the drive heats or cools, it takes a moment to recalibrate itself, but
that woouldn't occur at same spot on the drive every time.

if in doubt, run the WD diagnostics on it... something good to do with
a new drive anyway, if you hadn't already.



Dave

On 18 Dec 2003 07:47:23 -0800 Singing Yo-Ho-Ho and a Merry KMA
(E-Mail Removed) (anodos) wrote :

>The drive is a Western Digital 120 GB special edition (WD1200JB).
>While installing XP, I formatted the entire drive as a single NTFS
>partition (using the slow format to be sure and check for any surface
>errors). There were no bad sectors found during format. I then
>proceeded to test transfer rates from the drive. One of these tests
>involved creating several large files in XP and then reading them in
>as fast as possible. While testing one of these files (a 40 GB file),
>everything was humming along fine (47 MB/s transfer from the drive)
>until reaching a certain segment of the file (probably around 15 GB in
>size). In that segment, throughput dropped to around 1-3 MB/s. After
>passing the segment, transfer rates increased again. I performed the
>test a couple more times and verified that the same segment was
>reading slower. I then did a sequential read of the drive at a lower
>level, and it appears there are parts of the drive that just read
>slowly, dropping from 50-27MB/s down to 3-1MB/s. I never got any IO
>errors while performing any of these tests.
>My question is this: does anyone know why a drive would have large
>regions that read 10 times (or more) slower than other regions? I'm
>really hoping the answer is not that the hard drive is dying and that
>it is having to work hard at reading almost faulty sectors.
>
>Thanks,
> Anodos

Disable,"Indexing" on the drive and also,"Last File Name completion",
The free,"Regscrub" XP,
http://www.geocities.com/sheppola/freeprog.html
apart from being a good registry cleaner has option to disable some of
these in it's,"Misc" section.The Indexing you can do by right clicking
on the Hard drive properties etc.
More tweaks and info here,
http://www.winxpfix.com/
HTH



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