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POST: Why to never buy 3.5" external HDD's



 
 
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  #1  
Old April 1st 16, 02:11 PM posted to comp.sys.ibm.pc.hardware.storage
flo-rate
external usenet poster
 
Posts: 3
Default POST: Why to never buy 3.5" external HDD's

Interesting post. Is he right not to buy external 3.5 HDDs?

++++

http://forum.piriform.com/?showtopic=37513
Posted 24 December 2012 - 05:15 PM

Why to never buy 3.5" external HDD's? A good number of reasons. But 2.5"
are ok. If I haven't warned you guys & gals before then read up!

1- The drives that go into these external enclosures, like the WD MyBook
series for example, are sub-standard.

2- More surface errors. Externals have more errors on the surface right
out of the factory than their equivalent desktop models do. Every single
HDD ever made in the entire world has surface defects. But externals have
more than their desktop counterparts.

Every HDD comes with a bad sector map. The defective spots are recorded
in a chart and the drive skips over them, substituting a bad sector with
one from a reserve area. Thus the disk "presents" a 100% error free drive
to the OS. And in the old days, you had to manually enter the defective
sector list by hand according to certification chart taped to the drive
at time of mfg. Today it is stored in th firmware.

Accessing these spare areas takes a few mSec more than a normal
sequential sector - because the head has to swing to the reserve area.
This latency (for external disks) is buried out of sight deep inside the
USB interface. But on a hi-performace Enterprise class drive, speed loss
due to defect remappings are noticable and thus they get the best
platters.

3- Balance. You'll note that on average external drives generate more
vibration. This is from sub-standard bearings in the motor/spindle and
out of round platters. While each HDD (if you take it apart) seems ultra-
precise, there's a real difference when looking at their tolerances on a
microscopic scale.

4- Cheaper engineering. You'll find less cache in externals along with
single processor cores as opposed to 2 and 4 core controllers. That, and
number of heads. As the number of heads increase, the reliability
decreases. The desktop equivalent will have less surfaces, thus less
parts to fail, and fail they do!

5- Overall machining tolerances and materials are worse in the externals.
The materials are more sensitive to temperature changes, parts expand and
contract more, producing different geometries of the heads and surfaces,
and therefore requiring more compensation from the electronics to keep
things on track. Incidentally, this creates more heat. Typically 5-10`C.
Might as well throw in +5`C more due to rougher and less than "perfect"
machining of the bearings. And unbalanced platters require a bit more
current to keep them spinning steadily. More stress more heat. Unbalanced
platters add about 3`C to overall tempertature gain. All this consipires
to compound things. The metallic coating (where your data is stored) has
its coercivity affected by hotter temps, and presents a less defined
magnetic pattern.

6- Larger parts, platters, actuator arms, motors, bearings, fly-height
adjusters, micro-positioners, voice coils, things like that, it all takes
more power to operate.

7- Lack of any form of cooling! That's correct. There is no cooling fan
anywhere in most external disks! You're taking a desktop drive and
basically putting it into a box. No air circulation. You don't do this
with your desktop drives do you? You've got some kind of airflow, or if
not, you've got the disk attached to a metal frame that absorbs some
heat. In an external USB-style drive you don't any of those two cooling
mechanisms. You might as well put the disk in a baggie and then a shoe
box. This one factor alone is responsible for the high failure rate of
external disks! Externals can typically run 20-30`C higher than their
desktop cousins.

A hotter running disk from the get-go, trapped in a box with no
ventilation, is just asking for trouble. And manufacturers know this!
Evidenced by the shorter warranty 1-year vs. 3 or 5 years! They know the
disks will fail, they know about the lack of cooling as the #1 reason.
They are too cheap to put in a $5 fan, citing a number of excuses - one
of which, ironically, is extra moving parts.

---------------

I've seen Western Digital external drives run at a blistering 68`C !! How
can you expect a cheap consumer grade product to operate reliably under
those conditions. You can't! And I have to say that over the years I've
had many drives both professionally and personally, and without a doubt,
every single Western Digital 3.5" external disk that has no cooling fan
has died prematurely. ALL OF THEM! 100% fail.

Manufacturers expect this. They expect a short lifespan. They know this.
Remember that 1-year warranty as opposed to 3-years or 5-years!

It should be noted that 2.5" disks don't exhibit many of those cascading
failure scenarios. They are engineered to work in an enclosed compartment
with no ventilation. A laptop! They handle vibration better. Parts are
smaller, better spec'd. Less stress, less power consumption. Better
surface verification procedures. All a necessity with the higher density
of 2.5" platters and portable environment.

So if you're looking for external USB disks buy only 2.5", afterall these
smaller drives were engineered for the portable environment from the
ground up. They were not afterthoughts and hey let's do this types of
hacks.

And eventually, once SSD's become ready for the consumer market, then I
will recommend those. For now, stick with 1TB 2.5" externals for your
cost-effective storage needs.

Get two 1TB 2.5" disks as opposed to a single 2TB 3.5" external.

  #2  
Old April 1st 16, 04:39 PM posted to comp.sys.ibm.pc.hardware.storage
Mr. Man-wai Chang
external usenet poster
 
Posts: 697
Default POST: Why to never buy 3.5" external HDD's

On 1/04/2016 9:11 PM, flo-rate wrote:
Interesting post. Is he right not to buy external 3.5 HDDs?


Most 2.5 inch external hard disk are 5400RPM. I supposed 3.5 inch ones
could go 7200RPM. But then USB 3.0 might not be fast enough to handle
the increased data transfer rate.

Anyway, there are USB 3.0 and/or eSATA docking stations for both 2.5 and
3.5 inches ones, if you don't mind running a hard disk naked.

--
@~@ Remain silent. Nothing from soldiers and magicians is real!
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (Fedora release 23) Linux 4.4.6-300.fc23.x86_64
^ ^ 23:30:01 up 4 days 14:28 0 users load average: 1.01 1.03 1.05
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa
  #3  
Old April 1st 16, 04:40 PM posted to comp.sys.ibm.pc.hardware.storage
Mr. Man-wai Chang
external usenet poster
 
Posts: 697
Default POST: Why to never buy 3.5" external HDD's

On 1/04/2016 9:11 PM, flo-rate wrote:

Get two 1TB 2.5" disks as opposed to a single 2TB 3.5" external.


What if you need to backup more than 1TB of data? How do you draw the
line?

--
@~@ Remain silent. Nothing from soldiers and magicians is real!
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (Fedora release 23) Linux 4.4.6-300.fc23.x86_64
^ ^ 23:30:01 up 4 days 14:28 0 users load average: 1.01 1.03 1.05
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa
  #4  
Old April 1st 16, 05:37 PM posted to comp.sys.ibm.pc.hardware.storage
VanguardLH[_2_]
external usenet poster
 
Posts: 1,453
Default POST: Why to never buy 3.5" external HDD's

flo-rate wrote:

Interesting post. Is he right not to buy external 3.5 HDDs?

++++

http://forum.piriform.com/?showtopic=37513
Posted 24 December 2012 - 05:15 PM

Why to never buy 3.5" external HDD's? A good number of reasons. But 2.5"
are ok. If I haven't warned you guys & gals before then read up!

1- The drives that go into these external enclosures, like the WD MyBook
series for example, are sub-standard.

2- More surface errors. Externals have more errors on the surface right
out of the factory than their equivalent desktop models do. Every single
HDD ever made in the entire world has surface defects. But externals have
more than their desktop counterparts.

Every HDD comes with a bad sector map. The defective spots are recorded
in a chart and the drive skips over them, substituting a bad sector with
one from a reserve area. Thus the disk "presents" a 100% error free drive
to the OS. And in the old days, you had to manually enter the defective
sector list by hand according to certification chart taped to the drive
at time of mfg. Today it is stored in th firmware.

Accessing these spare areas takes a few mSec more than a normal
sequential sector - because the head has to swing to the reserve area.
This latency (for external disks) is buried out of sight deep inside the
USB interface. But on a hi-performace Enterprise class drive, speed loss
due to defect remappings are noticable and thus they get the best
platters.

3- Balance. You'll note that on average external drives generate more
vibration. This is from sub-standard bearings in the motor/spindle and
out of round platters. While each HDD (if you take it apart) seems ultra-
precise, there's a real difference when looking at their tolerances on a
microscopic scale.

4- Cheaper engineering. You'll find less cache in externals along with
single processor cores as opposed to 2 and 4 core controllers. That, and
number of heads. As the number of heads increase, the reliability
decreases. The desktop equivalent will have less surfaces, thus less
parts to fail, and fail they do!

5- Overall machining tolerances and materials are worse in the externals.
The materials are more sensitive to temperature changes, parts expand and
contract more, producing different geometries of the heads and surfaces,
and therefore requiring more compensation from the electronics to keep
things on track. Incidentally, this creates more heat. Typically 5-10`C.
Might as well throw in +5`C more due to rougher and less than "perfect"
machining of the bearings. And unbalanced platters require a bit more
current to keep them spinning steadily. More stress more heat. Unbalanced
platters add about 3`C to overall tempertature gain. All this consipires
to compound things. The metallic coating (where your data is stored) has
its coercivity affected by hotter temps, and presents a less defined
magnetic pattern.

6- Larger parts, platters, actuator arms, motors, bearings, fly-height
adjusters, micro-positioners, voice coils, things like that, it all takes
more power to operate.

7- Lack of any form of cooling! That's correct. There is no cooling fan
anywhere in most external disks! You're taking a desktop drive and
basically putting it into a box. No air circulation. You don't do this
with your desktop drives do you? You've got some kind of airflow, or if
not, you've got the disk attached to a metal frame that absorbs some
heat. In an external USB-style drive you don't any of those two cooling
mechanisms. You might as well put the disk in a baggie and then a shoe
box. This one factor alone is responsible for the high failure rate of
external disks! Externals can typically run 20-30`C higher than their
desktop cousins.

A hotter running disk from the get-go, trapped in a box with no
ventilation, is just asking for trouble. And manufacturers know this!
Evidenced by the shorter warranty 1-year vs. 3 or 5 years! They know the
disks will fail, they know about the lack of cooling as the #1 reason.
They are too cheap to put in a $5 fan, citing a number of excuses - one
of which, ironically, is extra moving parts.

---------------

I've seen Western Digital external drives run at a blistering 68`C !! How
can you expect a cheap consumer grade product to operate reliably under
those conditions. You can't! And I have to say that over the years I've
had many drives both professionally and personally, and without a doubt,
every single Western Digital 3.5" external disk that has no cooling fan
has died prematurely. ALL OF THEM! 100% fail.

Manufacturers expect this. They expect a short lifespan. They know this.
Remember that 1-year warranty as opposed to 3-years or 5-years!

It should be noted that 2.5" disks don't exhibit many of those cascading
failure scenarios. They are engineered to work in an enclosed compartment
with no ventilation. A laptop! They handle vibration better. Parts are
smaller, better spec'd. Less stress, less power consumption. Better
surface verification procedures. All a necessity with the higher density
of 2.5" platters and portable environment.

So if you're looking for external USB disks buy only 2.5", afterall these
smaller drives were engineered for the portable environment from the
ground up. They were not afterthoughts and hey let's do this types of
hacks.

And eventually, once SSD's become ready for the consumer market, then I
will recommend those. For now, stick with 1TB 2.5" externals for your
cost-effective storage needs.

Get two 1TB 2.5" disks as opposed to a single 2TB 3.5" external.


The problem with your analysis is that you imply there is a separate
production line with all the extra costs of additional tooling and
manpower to produce sub-standard external 3.5" HDDs. Those are produced
one the same assembly line using the same personnel using the same
tooling and the same parts as the internal 3.5" HDDs. The testing of
the finished product determines in which cost market the item gets sold.
This is the same with CPUs: those that can test at higher speed are
priced higher, those that fail the standard test but pass at slower
speed are priced lower. Same production line but resulting in different
grades of products. Nothing new here.

Also, the way you present your arguments is that a 3.5" or 2.5" external
drive requires that it be pre-built by someone else. Build your own.
Then you get to determine the quality of all the components. That's why
I still build my own home PC and why we build are own test rigs at work
for the alpha lab. They don't end up being cheaper than pre-builts
which are constructed based on specifications (so quality and brand and
model of components change depending on what the purchasing agent
decided to get cheapest that week). Instead of paying someone else
their overhead and profit margin for a pre-built, buy the components at
higher quality and, of course, higher priced. When you get done, your
own-built will be the same price, or a bit higher, because you aren't
charging yourself for your time and effort to build the thing but you
have higher-priced higher-quality gear.

Pre-built external HDDs are often built to be green. They power off or
spin down to save power. Some external HDDs have "green" drives which
make it impossible to use them for long backup jobs as the program will
eventually hang or timeout because the HDD won't wake up or take too
long to wakeup. Because of the cooling problem (with no fan and
non-ventilated cases), they need to keep the HDD spun down as often as
possible. Spinning up an HDD taxes its components: surge current
through the motor that experiences higher torque to start spinning the
stopped platters, heads no longer flying off the platter surface, surge
current through the electronics, and thermal flex due to change in
temperature. More power cycling an HDD results in a shorter lifespan.
If you build your own, you can stay away from green drives and use those
that are designed for 24x7 constant spinning usage. You can also pay
more money for enterprise-grade HDDs but your build won't be more
expensive because you're not paying you to build the external HDD. You
just pay for the parts.

Note that external HDDs rarely have active air circulation. There is no
fan (unless you build your own using a case that has a fan). That's why
pre-built external HDDs have slower rotating platters: less heat. The
pre-builts rely solely on convection to move the hot air away from the
HDD. When building your own, you can get a case with better passive
circulation (more and bigger ventilation holes) or even use a case with
a fan. Build your own and you get to choose the specifications and
quality of the parts that go into your build. External HDDs are pretty
easy to build. All pre-builts are sub-standard to what YOU can build
for the same cost to you.

So how hard is it to build your own external HDD (whether using good
quality 2.5" or 3.5" HDDs)? Not very. Slide the HDD inside the case,
connect the cables or slide the HDD into the connector, and close. The
hardest part is probably getting the tiny case screws to stay in place
until you get at them with the tiny screwdriver (so you'll need one if
not supplied). Of course, if YOU buy the cheapest components for the
build then you are doing the same thing the pre-builts are doing except
then they tack on their profit margin and overhead.

Which is better for quality: a pre-built sandwich you get out of a
vending machine or one you build yourself at home?
  #5  
Old April 1st 16, 06:42 PM posted to comp.sys.ibm.pc.hardware.storage
Lynn McGuire[_2_]
external usenet poster
 
Posts: 149
Default POST: Why to never buy 3.5" external HDD's

On 4/1/2016 8:11 AM, flo-rate wrote:
Interesting post. Is he right not to buy external 3.5 HDDs?

++++

http://forum.piriform.com/?showtopic=37513
Posted 24 December 2012 - 05:15 PM

Why to never buy 3.5" external HDD's? A good number of reasons. But 2.5"
are ok. If I haven't warned you guys & gals before then read up!


Nope. Especially when I need the 6 TB of space.

Lynn
  #6  
Old April 2nd 16, 02:58 AM posted to comp.sys.ibm.pc.hardware.storage
Ed Light
external usenet poster
 
Posts: 924
Default POST: Why to never buy 3.5" external HDD's

I have a WD external 3.5, and a couple of 2.5's.

The 3.5 I moved into a USB 3.0 case as it came as 2.0.

For long backups, I have to run a little desk fan at the 3.5 to keep it
cool, which works fine.

The 3.5 HD is indeed very slow and it does have a tiny cache. It's a
model meant for Tivos and the like.

The article is very old -- you can get a 3TB WD 2.5 now.

These drives come set to unload the heads after a certain timeo of
inactivity. It was only 3 seconds! I don't know what it is now. They
can't take as many unloads as you'd think. I use KeepAlive to make sure
they don't unload, by writing a little file every 2 seconds. Of course,
if you just hook the drive up for backups, then it's nothing to worry
about. If it's a file server, then you'd have to worry.

My WD 2.5 is actually a drive with a USB port in it as the only interface.

For convenience, easy storage, and the ability to be driven by a USB
port, the 2.5's win for me. I'll never buy another 3.5.
--
Ed Light

  #7  
Old April 2nd 16, 04:37 AM posted to comp.sys.ibm.pc.hardware.storage
Edward Diener
external usenet poster
 
Posts: 53
Default POST: Why to never buy 3.5" external HDD's

On 4/1/2016 9:11 AM, flo-rate wrote:
Interesting post. Is he right not to buy external 3.5 HDDs?

++++

http://forum.piriform.com/?showtopic=37513
Posted 24 December 2012 - 05:15 PM

Why to never buy 3.5" external HDD's? A good number of reasons. But 2.5"
are ok. If I haven't warned you guys & gals before then read up!

1- The drives that go into these external enclosures, like the WD MyBook
series for example, are sub-standard.

2- More surface errors. Externals have more errors on the surface right
out of the factory than their equivalent desktop models do. Every single
HDD ever made in the entire world has surface defects. But externals have
more than their desktop counterparts.


You buy a normal desktop drive. You buy an empty external enclosure,
which may house one or more drives. You insert your desktop drive into
the external enclosure and connect it to your computer via esata, usb,
firewire, or whatever and you have an external drive. Voila !

I learned early on that buying drives advertised as "external" drives in
some external enclosure is foolish. Then I bought an IcyDock external
enclosure with fans and easy connections, 3.5" desktop drives I have
used as backup drives in the external enclosure, and I couldn't be
happier. The enclosure is hot-swappable and has worked flawlessly as a
backup system, with Gparted Live or PartedMagic Live, or Minitools Live,
since I started using it.

The author of the article may be giving good advice not to buy 3.5"
drives advertised as external drives, but there is never any need to do
this as normal 3.5" desktop drives in an external enclosure works just fine.


  #8  
Old April 2nd 16, 01:29 PM posted to comp.sys.ibm.pc.hardware.storage
flo-rate
external usenet poster
 
Posts: 3
Default POST: Why to never buy 3.5" external HDD's

On Fri, 1 Apr 2016 11:37:43 -0500, VanguardLH wrote :
flo-rate wrote:

Interesting post. Is he right not to buy external 3.5 HDDs?

++++

http://forum.piriform.com/?showtopic=37513
Posted 24 December 2012 - 05:15 PM

Why to never buy 3.5" external HDD's? A good number of reasons. But 2.5"
are ok. If I haven't warned you guys & gals before then read up!

1- The drives that go into these external enclosures, like the WD MyBook
series for example, are sub-standard.

2- More surface errors. Externals have more errors on the surface right
out of the factory than their equivalent desktop models do. Every single
HDD ever made in the entire world has surface defects. But externals have
more than their desktop counterparts.

Every HDD comes with a bad sector map. The defective spots are recorded
in a chart and the drive skips over them, substituting a bad sector with
one from a reserve area. Thus the disk "presents" a 100% error free drive
to the OS. And in the old days, you had to manually enter the defective
sector list by hand according to certification chart taped to the drive
at time of mfg. Today it is stored in th firmware.

Accessing these spare areas takes a few mSec more than a normal
sequential sector - because the head has to swing to the reserve area.
This latency (for external disks) is buried out of sight deep inside the
USB interface. But on a hi-performace Enterprise class drive, speed loss
due to defect remappings are noticable and thus they get the best
platters.

3- Balance. You'll note that on average external drives generate more
vibration. This is from sub-standard bearings in the motor/spindle and
out of round platters. While each HDD (if you take it apart) seems ultra-
precise, there's a real difference when looking at their tolerances on a
microscopic scale.

4- Cheaper engineering. You'll find less cache in externals along with
single processor cores as opposed to 2 and 4 core controllers. That, and
number of heads. As the number of heads increase, the reliability
decreases. The desktop equivalent will have less surfaces, thus less
parts to fail, and fail they do!

5- Overall machining tolerances and materials are worse in the externals.
The materials are more sensitive to temperature changes, parts expand and
contract more, producing different geometries of the heads and surfaces,
and therefore requiring more compensation from the electronics to keep
things on track. Incidentally, this creates more heat. Typically 5-10`C.
Might as well throw in +5`C more due to rougher and less than "perfect"
machining of the bearings. And unbalanced platters require a bit more
current to keep them spinning steadily. More stress more heat. Unbalanced
platters add about 3`C to overall tempertature gain. All this consipires
to compound things. The metallic coating (where your data is stored) has
its coercivity affected by hotter temps, and presents a less defined
magnetic pattern.

6- Larger parts, platters, actuator arms, motors, bearings, fly-height
adjusters, micro-positioners, voice coils, things like that, it all takes
more power to operate.

7- Lack of any form of cooling! That's correct. There is no cooling fan
anywhere in most external disks! You're taking a desktop drive and
basically putting it into a box. No air circulation. You don't do this
with your desktop drives do you? You've got some kind of airflow, or if
not, you've got the disk attached to a metal frame that absorbs some
heat. In an external USB-style drive you don't any of those two cooling
mechanisms. You might as well put the disk in a baggie and then a shoe
box. This one factor alone is responsible for the high failure rate of
external disks! Externals can typically run 20-30`C higher than their
desktop cousins.

A hotter running disk from the get-go, trapped in a box with no
ventilation, is just asking for trouble. And manufacturers know this!
Evidenced by the shorter warranty 1-year vs. 3 or 5 years! They know the
disks will fail, they know about the lack of cooling as the #1 reason.
They are too cheap to put in a $5 fan, citing a number of excuses - one
of which, ironically, is extra moving parts.

---------------

I've seen Western Digital external drives run at a blistering 68`C !! How
can you expect a cheap consumer grade product to operate reliably under
those conditions. You can't! And I have to say that over the years I've
had many drives both professionally and personally, and without a doubt,
every single Western Digital 3.5" external disk that has no cooling fan
has died prematurely. ALL OF THEM! 100% fail.

Manufacturers expect this. They expect a short lifespan. They know this.
Remember that 1-year warranty as opposed to 3-years or 5-years!

It should be noted that 2.5" disks don't exhibit many of those cascading
failure scenarios. They are engineered to work in an enclosed compartment
with no ventilation. A laptop! They handle vibration better. Parts are
smaller, better spec'd. Less stress, less power consumption. Better
surface verification procedures. All a necessity with the higher density
of 2.5" platters and portable environment.

So if you're looking for external USB disks buy only 2.5", afterall these
smaller drives were engineered for the portable environment from the
ground up. They were not afterthoughts and hey let's do this types of
hacks.

And eventually, once SSD's become ready for the consumer market, then I
will recommend those. For now, stick with 1TB 2.5" externals for your
cost-effective storage needs.

Get two 1TB 2.5" disks as opposed to a single 2TB 3.5" external.


The problem with your analysis is that you imply there is a separate
production line with all the extra costs of additional tooling and
manpower to produce sub-standard external 3.5" HDDs. Those are produced
one the same assembly line using the same personnel using the same
tooling and the same parts as the internal 3.5" HDDs. The testing of
the finished product determines in which cost market the item gets sold.
This is the same with CPUs: those that can test at higher speed are
priced higher, those that fail the standard test but pass at slower
speed are priced lower. Same production line but resulting in different
grades of products. Nothing new here.

Also, the way you present your arguments is that a 3.5" or 2.5" external
drive requires that it be pre-built by someone else. Build your own.
Then you get to determine the quality of all the components. That's why
I still build my own home PC and why we build are own test rigs at work
for the alpha lab. They don't end up being cheaper than pre-builts
which are constructed based on specifications (so quality and brand and
model of components change depending on what the purchasing agent
decided to get cheapest that week). Instead of paying someone else
their overhead and profit margin for a pre-built, buy the components at
higher quality and, of course, higher priced. When you get done, your
own-built will be the same price, or a bit higher, because you aren't
charging yourself for your time and effort to build the thing but you
have higher-priced higher-quality gear.

Pre-built external HDDs are often built to be green. They power off or
spin down to save power. Some external HDDs have "green" drives which
make it impossible to use them for long backup jobs as the program will
eventually hang or timeout because the HDD won't wake up or take too
long to wakeup. Because of the cooling problem (with no fan and
non-ventilated cases), they need to keep the HDD spun down as often as
possible. Spinning up an HDD taxes its components: surge current
through the motor that experiences higher torque to start spinning the
stopped platters, heads no longer flying off the platter surface, surge
current through the electronics, and thermal flex due to change in
temperature. More power cycling an HDD results in a shorter lifespan.
If you build your own, you can stay away from green drives and use those
that are designed for 24x7 constant spinning usage. You can also pay
more money for enterprise-grade HDDs but your build won't be more
expensive because you're not paying you to build the external HDD. You
just pay for the parts.

Note that external HDDs rarely have active air circulation. There is no
fan (unless you build your own using a case that has a fan). That's why
pre-built external HDDs have slower rotating platters: less heat. The
pre-builts rely solely on convection to move the hot air away from the
HDD. When building your own, you can get a case with better passive
circulation (more and bigger ventilation holes) or even use a case with
a fan. Build your own and you get to choose the specifications and
quality of the parts that go into your build. External HDDs are pretty
easy to build. All pre-builts are sub-standard to what YOU can build
for the same cost to you.

So how hard is it to build your own external HDD (whether using good
quality 2.5" or 3.5" HDDs)? Not very. Slide the HDD inside the case,
connect the cables or slide the HDD into the connector, and close. The
hardest part is probably getting the tiny case screws to stay in place
until you get at them with the tiny screwdriver (so you'll need one if
not supplied). Of course, if YOU buy the cheapest components for the
build then you are doing the same thing the pre-builts are doing except
then they tack on their profit margin and overhead.

Which is better for quality: a pre-built sandwich you get out of a
vending machine or one you build yourself at home?




The post I quoted says lower spec hard drives get supplied as 3.5 inch
external drives. This is very unlikely to be done by running different
production lines of different qualities but by tests to determine which
are substandard for use as an internal drive. That's how I read it and
that's what he is describing.

As you say, you could get around this problem by buying your own internal
3.5 inch drive and mounting it in a carrier with USB lead. The author
suggests it's better still to buy an external 2.5 inch drive.

In other words, external 3.5 inch drives are low spec drives derived from
a design for internal use but external 2.5 inch drives are designed to do
a better job and they seem to do it.

One big problem is if you look inside what is supplied as an external 2.5
inch drive then it's anyone's guess which particular model/manufacturer
drive was been used. E.G. Seagate changes between using Samsung Spinpoint
or Seagate Barracuda drives for the same capacity enclosure. Also there
are additonal variations from 2.5 inch drive thickness which is likely
determined by the number of platters and, in turn, the platter density.

So, even accepting, the poster's proposition that external 2.5 inch
drives in general are better than 3.5 inch external drives, there is no
easy way of telling what is inside an external 2.5 inch drive's enclosure
that a particular review is testing. This would affect transfer rate,
seek times, power requirement, etc. For this reason it may be better to
follow your suggestion and buy an internal 3.5 inch drive of known
performance (from reviews) and use it as an external drive. But who want
an heavy old hot clunker of a 3.5 inch drive with it's own external power
supply?

One answer could be to buy a known internal 2.5 inch drive whose spec you
like and mount it in an external USB enclosure.



  #9  
Old April 2nd 16, 04:35 PM posted to comp.sys.ibm.pc.hardware.storage
VanguardLH[_2_]
external usenet poster
 
Posts: 1,453
Default POST: Why to never buy 3.5" external HDD's

flo-rate wrote:

One answer could be to buy a known internal 2.5 inch drive whose spec you
like and mount it in an external USB enclosure.


At newegg.com, I can find a 3.5" 8 TB 7200 RPM drive at $440. For a
2.5" 7200 RPM laptop HDD, the biggest they carry is 2 TB costing $990.
With the 3.5" form factor, I get 4 times the capacity at less than half
the cost.

Yeah, 2.5" is technically doable but at a much greater cost per byte.
Of course, a 2.5" external HDD will probably fit [tightly] in your shirt
pocket (as long as there is no fan) but you'll need to tote the 3.5".
Who carries their 2.5" external HDD in their shirt pocket?
  #10  
Old April 2nd 16, 07:40 PM posted to comp.sys.ibm.pc.hardware.storage
flo-rate
external usenet poster
 
Posts: 3
Default POST: Why to never buy 3.5" external HDD's

On Sat, 2 Apr 2016 10:35:06 -0500, VanguardLH wrote :
flo-rate wrote:

One answer could be to buy a known internal 2.5 inch drive whose spec you
like and mount it in an external USB enclosure.


At newegg.com, I can find a 3.5" 8 TB 7200 RPM drive at $440. For a
2.5" 7200 RPM laptop HDD, the biggest they carry is 2 TB costing $990.
With the 3.5" form factor, I get 4 times the capacity at less than half
the cost.

Yeah, 2.5" is technically doable but at a much greater cost per byte.
Of course, a 2.5" external HDD will probably fit [tightly] in your shirt
pocket (as long as there is no fan) but you'll need to tote the 3.5".
Who carries their 2.5" external HDD in their shirt pocket?


Check those prices. Here are a 3.5 and a 2.5 drive chosen at random. Both
of the same capacity for comparison.

A Seagate 3.5-Inch 4TB Desktop HDD costs $115.
http://www.amazon.com/dp/B00B99JU4S/

A Samsung Momentus 4TB 2.5-inch Hard Drive costs $140.
http://www.amazon.com/dp/B00B99JU4S/

 




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