Strange behaviour 2 wd hdd's

[pieter]

Hello There, could have a little help to fix a very weird problem of two of my wd hdd's of a total of three.
This is what i have:
HDD1: WD10EADS 1TB Drive M
HDD2: WD10EADS 1TB Drive V
HDD3: WD10EARS 1TB Drive E

All three drives are working normally, exept two of them behave strangly when transferring smaller files from one to another
ie: a folder wich contains foto's of about 800Mb wiil have a dramatacly dropdown of average transfer rate when starting to copy from one drive to another under windows commander it starts with around 37Mb/s but shortly after it falls back to 1,7Kb/s,... execpt for one drive it reamains speed at average 30-40Mb/s
Doing the test with larger (video files) there's no problem whatsoever.
The strange part,... Drive M does not have these problems at all but drive V, and E do.
Exchanging the drive from the sata bus, delete drivers, repartition the drives, low level format, etc,etc on all three drives does not change the behaviour, it stays at 2 drives ie: one WD10EADS and one WD10EARS
Even moving it out of the pc and make it an external one, no change either, behaviour moves with the drives .
So 2 out of three HDD's have this behaviour
Stranger it becomes that i have two exact the same drives with same firmware and even very close serial number, one is affected one not.
Now i did use wd diagnostic tools to figure it out, came out all ok no defects encounterd.
Also S.M.A.R.T from w.d. no errors either.
Then i tried disk info
Now things changed a bit on two of the drives (affected ones) Current Pending sector count came up with: 0000000000001
But that is all, Reallocated sector count are all zero's, also error count zero's too
Exept for hours running etc,etc, all values are the same exept for this one.
If i understood it correct when a file tries to acces this "sector" again it should move to the reallocated sector count and current pending sector should become zero again if the sector is broken.
I have tried just about anything i could think of to get the jobe done but no results.
Remove entire partition, create a new one change format (NTFS/FAT) Full erase, dos format CHKDSK/R etc,etc,etc,
Nothing but nothing will change this value.
I am almost certain that this report in S.M.A.R.T has something to do with this beahviour, at least it makes some sense to me.
When driving a car around the courner without knowing if there's a road block or not means i have to slow down too otherwise i would ram the roadblock if it exsists, knowing the roadblock (Reallocated sector count) would make me change my direction driving the car
Has anyone out there any ideas on how to fix this?

[northwind]

What is really strange is that you tried with two other disks and one of them is behaving the same.

Did you try on another machine? Some other pc?

It seems to me that there are some bad sectors on the disk, which makes sense (as you said too), that transfer slows down, but then again, transfer rates should flanctuate i guess.

Not sure. Try on another machine and let us know. This is weird to me.

[Vulcan]

@pieter:

Have you collected "read throughput" benchmark graphs of the 3 disks (e.g. using HDTune / HDDScan etc.) and compared the graphs?

[ludop2]

It is normal for this CAVIAR Green WD. Green means low power for protect environmemt so the rpm of motor is adjustable between 5400 and 7200 to save energy. These WD are very slow for copying small files. Go here
http://www.hardware.fr/articles/799-1/c ... -1-to.html
but sorry it is in french but i think you can understand.
These WD caviar Green have many pb and it is not esay to recover data on them so make a copy of your important data. If you want good WD take WD CAVIAR black.
ludop

[fzabkar]

It is normal for this CAVIAR Green WD. Green means low power for protect environmemt so the rpm of motor is adjustable between 5400 and 7200 to save energy.

With respect, you have been misled by WD's deceptive IntelliPower marketingspeak.

WD's marketing blurbs state that "for each drive model, WD may use a different, invariable RPM." That means that a particular model is designed to spin at a fixed speed. AFAICT, most (all?) Intellipower drives are spinning at 5400 RPM.

See this article which actually measures the speed by analysing the sound spectrum:
http://www.silentpcreview.com/article786-page2.html

Otherwise you can estimate the speed from HD Tune's access time graph:
http://groups.google.com/group/comp.sys ... 36d4afc140