IDE or AHCI ?

What is the fastest hard drive access method for
Windows 7 x64, IDE or AHCI ? I have a WD 1 TB
caviar black, a Gigabyte z68xp-ud5 motherboard
and a Intel I3-2500K with 8 GB of ram.

I see these thoughts:
http://expertester.wordpress.com/200...ark-advantage/
http://tweaks.com/windows/44119/impr...m-ide-to-ahci/

Thanks,
Lynn

Lynn McGuire wrote:
What is the fastest hard drive access method for
Windows 7 x64, IDE or AHCI ? I have a WD 1 TB
caviar black, a Gigabyte z68xp-ud5 motherboard
and a Intel I3-2500K with 8 GB of ram.

I see these thoughts:
http://expertester.wordpress.com/200...ark-advantage/
http://tweaks.com/windows/44119/impr...m-ide-to-ahci/

Thanks,
Lynn

It should not matter much for speed. AHCI has hotplug, IDE does
not though. And AHCI dirvers may be newer, improving speed.
Unfortunately even Win 7 has problematic (no?) AHCI support out
of the box and requires drivers. AFAIK this is motsly an issue for
new installations. Under Linux it does not matter.

Arno
--
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email:
GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

Arno wrote:
Lynn McGuire wrote:

What is the fastest hard drive access method for
Windows 7 x64, IDE or AHCI ? I have a WD 1 TB
caviar black, a Gigabyte z68xp-ud5 motherboard
and a Intel I3-2500K with 8 GB of ram.

I see these thoughts:

http://expertester.wordpress.com/200...ark-advantage/
http://tweaks.com/windows/44119/impr...m-ide-to-ahci/

It should not matter much for speed. AHCI has hotplug, IDE does
not though. And AHCI dirvers may be newer, improving speed.
Unfortunately even Win 7 has problematic (no?) AHCI support out
of the box and requires drivers.

Wrong, as always.

AFAIK this is motsly an issue for new installations.

Wrong, as always.

Under Linux it does not matter.

Wrong, as always. The difference isnt huge, but the first set of benchmarks show that the effect is real.

Lynn McGuire wrote:

What is the fastest hard drive access method for Windows 7 x64, IDE or AHCI ?

There clearly isnt a lot in it give the stats in your first link.

I doubt you'd be able to pick the difference in a proper double blind
trial without being allowed to use a benchmark with normal work.

If you can, with normal work, use the config which gives the best result WITH THAT WORK.

I have a WD 1 TB caviar black, a Gigabyte z68xp-ud5 motherboard and a Intel I3-2500K with 8 GB of ram.

I see these thoughts:

http://expertester.wordpress.com/200...ark-advantage/
http://tweaks.com/windows/44119/impr...m-ide-to-ahci/

On 03/01/2012 1:30 PM, Lynn McGuire wrote:
What is the fastest hard drive access method for
Windows 7 x64, IDE or AHCI ? I have a WD 1 TB
caviar black, a Gigabyte z68xp-ud5 motherboard
and a Intel I3-2500K with 8 GB of ram.

I see these thoughts:
http://expertester.wordpress.com/200...ark-advantage/

http://tweaks.com/windows/44119/impr...m-ide-to-ahci/

I did the switch to AHCI back in the Windows XP days. At that time it
was a difficult transition as there were no default AHCI drivers, and
switching to AHCI without doing some preparation meant that your OS
would not boot. It's still not an easy switch with Windows 7 either, you
basically have to install Windows 7 with AHCI already enabled or else
it'll default to IDE and not include the AHCI drivers in the install.
Otherwise, switching to AHCI after installing Win 7 is already installed
is nearly as difficult as XP. Linux could use either type transparently,
not sure why Microsoft didn't make it as simple with its own drivers.

After doing the switch, I find absolutely no difference in performance.
However, I do have an external eSATA drive which can be enabled and
disabled on the fly just like a USB drive. I think if I were still using
IDE drivers, that wouldn't be nearly as easy though.

Yousuf Khan

On 04/01/2012 06:07, Yousuf Khan wrote:
On 03/01/2012 1:30 PM, Lynn McGuire wrote:
What is the fastest hard drive access method for Windows 7 x64, IDE
or AHCI ? I have a WD 1 TB caviar black, a Gigabyte z68xp-ud5
motherboard and a Intel I3-2500K with 8 GB of ram.

I see these thoughts:
http://expertester.wordpress.com/200...ark-advantage/



http://tweaks.com/windows/44119/impr...m-ide-to-ahci/



I did the switch to AHCI back in the Windows XP days. At that time it
was a difficult transition as there were no default AHCI drivers,
and switching to AHCI without doing some preparation meant that your
OS would not boot. It's still not an easy switch with Windows 7
either, you basically have to install Windows 7 with AHCI already
enabled or else it'll default to IDE and not include the AHCI drivers
in the install. Otherwise, switching to AHCI after installing Win 7
is already installed is nearly as difficult as XP. Linux could use
either type transparently, not sure why Microsoft didn't make it as
simple with its own drivers.


It's hard to comprehend MS's difficulty here. There is little
measurable difference in performance between IDE mode and AHCI mode, but
people often /perceive/ "native SATA" mode as newer and faster than "IDE
emulation" mode. So even if you can't measure a difference, it still
seems absurd that you have to jump through hoops to run "native SATA".

After doing the switch, I find absolutely no difference in
performance. However, I do have an external eSATA drive which can be
enabled and disabled on the fly just like a USB drive. I think if I
were still using IDE drivers, that wouldn't be nearly as easy
though.


There are two main differences in practice between SATA and IDE modes.
One is hotplug, as you mentioned, and the other is NCQ - native command
queueing. (There are also a few other SATA commands, such as SSD trim
and secure erase.)

NCQ won't make a significant difference in Linux, since it has always
had good algorithms to order disk accesses to minimise head movement.
It will sometimes make things worse, such as when the OS wants to
enforce a particular order (for transactions to filesystem journals, for
example). And NCQ doesn't help windows much either - after all, it only
applies when you do more than one thing at a time.

David Brown wrote
Yousuf Khan wrote
Lynn McGuire wrote

What is the fastest hard drive access method for Windows 7 x64, IDE or AHCI ? I have a WD 1 TB caviar black, a
Gigabyte z68xp-ud5
motherboard and a Intel I3-2500K with 8 GB of ram.

I see these thoughts:
http://expertester.wordpress.com/200...ark-advantage/
http://tweaks.com/windows/44119/impr...m-ide-to-ahci/

I did the switch to AHCI back in the Windows XP days. At that time it was a difficult transition as there were no
default AHCI drivers,
and switching to AHCI without doing some preparation meant that your OS would not boot. It's still not an easy switch
with Windows 7
either, you basically have to install Windows 7 with AHCI already
enabled or else it'll default to IDE and not include the AHCI drivers
in the install. Otherwise, switching to AHCI after installing Win 7
is already installed is nearly as difficult as XP. Linux could use
either type transparently, not sure why Microsoft didn't make it as
simple with its own drivers.

It's hard to comprehend MS's difficulty here.

For you, sure.

There is little measurable difference in performance between IDE mode and AHCI mode,

Yes.

but people often /perceive/ "native SATA" mode as newer and faster than "IDE emulation" mode.

More fool them.

So even if you can't measure a difference,

Corse you can.

it still seems absurd that you have to jump through hoops to run "native SATA".

Why when the difference is so trivial ?

After doing the switch, I find absolutely no difference in performance. However, I do have an external eSATA drive
which can be enabled and disabled on the fly just like a USB drive. I think if I were still using IDE drivers, that
wouldn't be nearly as easy though.

There are two main differences in practice between SATA and IDE modes.
One is hotplug, as you mentioned, and the other is NCQ - native command queueing. (There are also a few other SATA
commands, such as SSD trim and secure erase.)

NCQ won't make a significant difference in Linux, since it has always
had good algorithms to order disk accesses to minimise head movement.

And so does Win.

It will sometimes make things worse, such as when the OS wants to enforce a particular order (for transactions to
filesystem journals,
for example). And NCQ doesn't help windows much either

Wrong.

- after all, it only applies when you do more than one thing at a time.

Which Win does all the time.

On 04/01/2012 10:32, Rod Speed wrote:
David Brown wrote
Yousuf Khan wrote
Lynn McGuire wrote

What is the fastest hard drive access method for Windows 7 x64,
IDE or AHCI ? I have a WD 1 TB caviar black, a Gigabyte
z68xp-ud5 motherboard and a Intel I3-2500K with 8 GB of ram.

I see these thoughts:
http://expertester.wordpress.com/200...ark-advantage/

http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/

I did the switch to AHCI back in the Windows XP days. At that
time it was a difficult transition as there were no default AHCI
drivers, and switching to AHCI without doing some preparation
meant that your OS would not boot. It's still not an easy switch
with Windows 7 either, you basically have to install Windows 7
with AHCI already enabled or else it'll default to IDE and not
include the AHCI drivers in the install. Otherwise, switching to
AHCI after installing Win 7 is already installed is nearly as
difficult as XP. Linux could use either type transparently, not
sure why Microsoft didn't make it as simple with its own
drivers.

It's hard to comprehend MS's difficulty here.

For you, sure.

There is little measurable difference in performance between IDE
mode and AHCI mode,

Yes.

but people often /perceive/ "native SATA" mode as newer and faster
than "IDE emulation" mode.

More fool them.

So even if you can't measure a difference,

Corse you can.

it still seems absurd that you have to jump through hoops to run
"native SATA".

Why when the difference is so trivial ?

You do realise you are arguing against yourself here, don't you? First
you agree that there is only a trivial difference in performance between
IDE and AHCI modes, then you argue that "of course" you can measure it,
then you argue that there is little point in using it (on Windows) since
the differences are trivial...

Back to reality. Yes, the performance differences are trivial. Yes,
they /can/ be measured - but the differences are below the noise
threshold for most windows machines. To measure them, you have to be
careful about test conditions, background services, repetition of the
tests, clean installs, etc. That's fine for a website specialising in
tests and benchmarks, but of little use to most people.

However, whatever the technical benefits (or lack thereof) of using AHCI
instead of IDE, user perception and expectation should be important to a
supplier like MS. The effort needed to get hard drive drivers in place
and working in Windows, and the scope for getting it wrong and causing
problems, is just silly when you look at how simple it is with Linux.


After doing the switch, I find absolutely no difference in
performance. However, I do have an external eSATA drive which can
be enabled and disabled on the fly just like a USB drive. I think
if I were still using IDE drivers, that wouldn't be nearly as
easy though.

There are two main differences in practice between SATA and IDE
modes. One is hotplug, as you mentioned, and the other is NCQ -
native command queueing. (There are also a few other SATA
commands, such as SSD trim and secure erase.)

NCQ won't make a significant difference in Linux, since it has
always had good algorithms to order disk accesses to minimise head
movement.

And so does Win.

I wasn't talking about Windows here.


It will sometimes make things worse, such as when the OS wants to
enforce a particular order (for transactions to filesystem
journals, for example). And NCQ doesn't help windows much either

Wrong.


No, it is correct - NCQ doesn't help windows much. Benchmarks vary, as
it depends heavily on the usage patterns. It is a win in some cases,
and a loss on others - but seldom by particularly large margins.

- after all, it only applies when you do more than one thing at a
time.

Which Win does all the time.



I knew that would provoke you :-)

On 04/01/2012 2:53 AM, David Brown wrote:
NCQ won't make a significant difference in Linux, since it has always
had good algorithms to order disk accesses to minimise head movement. It
will sometimes make things worse, such as when the OS wants to enforce a
particular order (for transactions to filesystem journals, for example).
And NCQ doesn't help windows much either - after all, it only applies
when you do more than one thing at a time.

I find that it doesn't even help even when multitasking. I monitor the
disk subsection of the Resource Monitor regularly, and very often when
the disk is busy the Disk Queue Length is over 1.00 (meaning more than 1
process is actively waiting on the disk) and the Active Time is pegged
near 100%. Nothing that can be done about it till SSD's are more affordable.

Yousuf Khan

On 04/01/2012 15:29, Yousuf Khan wrote:
On 04/01/2012 2:53 AM, David Brown wrote:
NCQ won't make a significant difference in Linux, since it has always
had good algorithms to order disk accesses to minimise head movement. It
will sometimes make things worse, such as when the OS wants to enforce a
particular order (for transactions to filesystem journals, for example).
And NCQ doesn't help windows much either - after all, it only applies
when you do more than one thing at a time.

I find that it doesn't even help even when multitasking. I monitor the
disk subsection of the Resource Monitor regularly, and very often when
the disk is busy the Disk Queue Length is over 1.00 (meaning more than 1
process is actively waiting on the disk) and the Active Time is pegged
near 100%. Nothing that can be done about it till SSD's are more
affordable.

Yousuf Khan

NCQ can only really help if you have multiple outstanding transactions,
and the OS itself hasn't ordered them appropriately. Since the OS
(Windows or Linux) /does/ order transactions, NCQ will only help if the
OS is doing a bad job. The disk knows a bit more than the OS regarding
disk ordering (since it knows the full 3D geometry, rather than just a
linear LBA number), but on the other hand it knows nothing about which
processes are waiting for disk access, or the priorities of said
accesses, and it knows nothing about barrier writes. I don't know how
Windows handles write barriers, but on Linux they are important to
ensure the integrity of critical disk accesses such as journalling -
they ensure that everything that was supposed to be written earlier
/has/ been written. NCQ totally screws this up, and means that the OS's
IO subsystem must ensure the disk queue is completely empty before
sending the barrier write, and wait for it to finish completely before
sending anything else. If the disk handles transactions in the order
they are given, then such writes can be buffered better.