Slow write speeds on a WD 500GB drive

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bbbl67

A friend of mine had an WD My Book external case, which contained a
500GB WDC WD5000AAVS-00ZTB0 hard drive inside it. At some point along
the way the My Book's interface failed, it's warranty was expired, and
so we took its hard drive out and installed it directly inside his PC
case. This was back in mid- to late-2011, that it was transferred from
external to internal. It seemed to be fine for the most part in
performance, but recently we did some benchmarking and we were shocked
to find that although its reading speeds seem normal (around 50-60 MB/
s), its write speeds were shockingly low (around 10 MB/s, if even
that). What could cause such a weird asymmetry in read vs. write
speeds? It didn't seem that slow while it was inside the My Book case.

This is one of those WD Caviar Green drives, so I'm wondering if there
is some kind of power savings setting affecting it?

Yousuf Khan
 
bbbl67 said:
A friend of mine had an WD My Book external case, which contained a
500GB WDC WD5000AAVS-00ZTB0 hard drive inside it. At some point
along the way the My Book's interface failed, it's warranty was expired,
and so we took its hard drive out and installed it directly inside his PC
case. This was back in mid- to late-2011, that it was transferred from
external to internal. It seemed to be fine for the most part in
performance,
but recently we did some benchmarking and we were shocked to find
that although its reading speeds seem normal (around 50-60 MB/
s), its write speeds were shockingly low (around 10 MB/s, if even
that). What could cause such a weird asymmetry in read vs. write
speeds? It didn't seem that slow while it was inside the My Book case.
Click to expand...
This is one of those WD Caviar Green drives, so I'm wondering if there
is some kind of power savings setting affecting it?
Click to expand...

Cant see why any of those would produce that effect only with writes.

They are mostly just 5400 RPM drives to get the 'green' result.

You sure its hasn't got verify after write turned on ?

Why have you changed your nick but kept the email address unmunged ?
 
Cant see why any of those would produce that effect only with writes.

They are mostly just 5400 RPM drives to get the 'green' result.
Click to expand...

The specs seem to just try to hide the speed behind some marketing
term called IntelliSpeed or something.
You sure its hasn't got verify after write turned on ?
Click to expand...

What is that? It sounds like something you do in software.
Why have you changed your nick but kept the email address unmunged ?
Click to expand...

I'm posting from Google groups, that's all.
 
bbbl67 said:
A friend of mine had an WD My Book external case, which contained a
500GB WDC WD5000AAVS-00ZTB0 hard drive inside it. At some point along
the way the My Book's interface failed, it's warranty was expired, and
so we took its hard drive out and installed it directly inside his PC
case. This was back in mid- to late-2011, that it was transferred from
external to internal. It seemed to be fine for the most part in
performance, but recently we did some benchmarking and we were shocked
to find that although its reading speeds seem normal (around 50-60 MB/
s), its write speeds were shockingly low (around 10 MB/s, if even
that). What could cause such a weird asymmetry in read vs. write
speeds? It didn't seem that slow while it was inside the My Book case.
Click to expand...

From my experience, this sounds like the drive has problems
positioning or finding sectors. If it was finding sectrors, then
the read-speed should also be affected. My guess would be weak
power or vibration that makes the more precise head positioning on
writes difficult.
This is one of those WD Caviar Green drives, so I'm wondering if there
is some kind of power savings setting affecting it?
Click to expand...

Not that bad.

Arno
 
The specs seem to just try to hide the speed behind some marketing
term called IntelliSpeed or something.
Click to expand...

5400 rpm is only 25% less. Thoughput is usualy comparable
as the lower speed allows for higher data density.
What is that? It sounds like something you do in software.
Click to expand...

It used to be a software setting for floppy disks in the DOS age
and it is just as irrrelevant today. It would also only about halve t
he speed, not bring it down as much as you see.

Just Rod's usual atrocious lack of insight at work.

Arno
 
From my experience, this sounds like the drive has problems
positioning or finding sectors. If it was finding sectrors, then
the read-speed should also be affected. My guess would be weak
power or vibration that makes the more precise head positioning on
writes difficult.


Not that bad.
Click to expand...

I'm gonna switch it to the IDE driver to see if it fixes it somehow
today.

Yousuf Khan
 
Hmm. The write speed is pretty consistent and on the level of
512B writes. Maybe multi-sector transfer is off?
Click to expand...

The drive also has one bad sector on it (actually uncorrectable sector),
but I can't see that causing the entire drive to become nearly unwritable.

Yousuf Khan
 
The specs seem to just try to hide the speed behind
some marketing term called IntelliSpeed or something.
Click to expand...

Yeah, tho the datasheets do spell that out with all the ones I have checked.
What is that?
Click to expand...

Basically the drive reads what has just been
ritten and checks that it can read it fine.
It sounds like something you do in software.
Click to expand...

Most drives can have it enabled.

In fact one family of drives, Maxtors from memory,
used to have it on by default with new drives and
turned it off auto when they drive had done X
power on hours or # or writes, forget which.

Basically it was someone's idea for how to wring the
maximum capacity out of a drive, be conservative
about the initial factory bad block scan and let the
drive remap new bads with that verify after write
ensuring that the users data was safe.

Dunno how many others followed that approach or if any still do.
I'm posting from Google groups, that's all.
Click to expand...

But why cant you use your normal name with that too ?

I can when posting from groups.google.
 
5400 rpm is only 25% less.
Click to expand...

I clearly said that that isnt the reason for just the writes being affected.
Thoughput is usualy comparable as the
lower speed allows for higher data density.
Click to expand...

That’s just plain wrong with those ecogreen drives.

If it was that simple they wouldn’t sell the non green drives too.
It used to be a software setting for floppy disks in the DOS age
Click to expand...

Its actually part of the ATA standard.
and it is just as irrrelevant today.
Click to expand...

Wrong, as always.
It would also only about halve the speed,
not bring it down as much as you see.
Click to expand...

Only if it isnt have a problem with the writes.
Just Rod's usual atrocious lack of insight at work.
Click to expand...

Guess which pathetic little posturing drunk has
just got egg all over its stupid little face, as always ?

--
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP --
Click to expand...

You should have a jpg of your dick appended...
 
Most drives can have it enabled.

In fact one family of drives, Maxtors from memory,
used to have it on by default with new drives and
turned it off auto when they drive had done X
power on hours or # or writes, forget which.

Basically it was someone's idea for how to wring the
maximum capacity out of a drive, be conservative
about the initial factory bad block scan and let the
drive remap new bads with that verify after write
ensuring that the users data was safe.
Click to expand...

That would actually explain why my old IDE Maxtors were so bullet proof,
even five years later. Other drives had several sectors remapped, or
even unrecoverable, after only a few months, but these Maxtors stayed
error-free after half-a-decade. Ironically I just finally got rid of
those Maxtors this week too.
But why cant you use your normal name with that too ?

I can when posting from groups.google.
Click to expand...


I only use it when I'm posting from someone else's computer. It simply
was setup that way from before.

Yousuf Khan
 
I'd try another benchmark to see if that one is getting royally confused
somehow.
Click to expand...

It's the only benchmark that would run on that drive. CrystalMark took
forever just to write a test file to it. Even a "quick" format of the
drive was dog-slow.

Yousuf Khan
 
Yousuf Khan said:
Rod Speed wrote
Click to expand...

That should have read, be LESS CONSERVATIVE
That would actually explain why my old IDE
Maxtors were so bullet proof, even five years later.
Click to expand...

It doesn't, actually.
Other drives had several sectors remapped, or
even unrecoverable, after only a few months,
Click to expand...

Mine never did.
but these Maxtors stayed error-free after half-a-decade.
Click to expand...

But that approach should have seen the Maxtors
produce more remapped sectors early on than
otherwise. Sorry I rarely bother to proof read.
Ironically I just finally got rid of those Maxtors this week too.
Click to expand...

They were actually notorious for dying
easier than most of not adequately cooled.
I only use it when I'm posting from someone else's computer.
OK.

It simply was setup that way from before.
Click to expand...

Yeah, I can see why too given that its your yahoo.com email address.
 
Yousuf Khan said:
Rod Speed wrote
Click to expand...
It's the only benchmark that would run on that drive.
Click to expand...
CrystalMark took forever just to write a test file to it. Even a "quick"
format of the drive was dog-slow.
Click to expand...

That does support the claim that the drive really is very slow
to write when its not just a benchmark that claims that.

I'd try the drive in another system myself in case its actually
a problem with the machine or the controller, not the drive.
 
The drive also has one bad sector on it (actually uncorrectable sector),
but I can't see that causing the entire drive to become nearly unwritable.
Click to expand...
Yousuf Khan
Click to expand...

I think the consistnt write rate points to some limiting factor
that is far more constant than a hardware problem. Unless the
disk has decided to limit its write rate due to such a problem.
Would be news to me, but sich a behaviour can certainly be
implemented.

Well, frankly I don't know. I would not trust this drive though.

Arno
 
The drive also has one bad sector on it (actually uncorrectable sector),
but I can't see that causing the entire drive to become nearly unwritable.
Click to expand...

Perhaps bad sectors are like cockroaches. When you see one, there may
be a lot more that you don't see.

In any case, AFAICS, bad sectors, or heads with weak read elements,
would show up during reads more so than writes.

- Franc Zabkar
 
I think the consistnt write rate points to some limiting factor
that is far more constant than a hardware problem. Unless the
disk has decided to limit its write rate due to such a problem.
Would be news to me, but sich a behaviour can certainly be
implemented.

Well, frankly I don't know. I would not trust this drive though.
Click to expand...

Well, either would I, so I exchanged it with a different WD 500GB drive
for him. I took his old 500GB drive and put it into an eSATA case and I
am now testing it on my own system. I'll run a full SMART test on it.

Yousuf Khan
 
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