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Groups > comp.sys.ibm.pc.hardware.storage > #2262

Re: IDE or AHCI ?

From Arno <me@privacy.net>
Newsgroups comp.sys.ibm.pc.hardware.storage
Subject Re: IDE or AHCI ?
Date 2012-01-04 19:14 +0000
Message-ID <9mjmo2FocqU1@mid.individual.net> (permalink)
References <jdvhfu$5o3$1@dont-email.me> <4f03de83$1@news.bnb-lp.com> <hPWdnT07Memqm5nSnZ2dnUVZ7oadnZ2d@lyse.net>

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David Brown <david@westcontrol.removethisbit.com> wrote:
> 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/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-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.  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".

Indeed. And you onlu get reliably working hotplug with AHCI,
which is a factor for eSATA. Basically shows that when it
comes to things on the hardcore tech layer, MS is still
pretty far behind.

>> 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.

Indeed again. NCQ is motsly for server loads, where a lot
of things run in parallel, with a sub-standard buffer-cache.
This certainly does not apply to Linux or the BSDs. No
idea whether it applies to Windows on servers. 

Arno
-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name
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

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Thread

IDE or AHCI ? Lynn McGuire <lmc@winsim.com> - 2012-01-03 12:30 -0600
  Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-03 21:05 +0000
    Re: IDE or AHCI ? "arno fucker" <af@arnofucker.com> - 2012-01-04 12:41 +1100
  Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-04 12:58 +1100
  Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-04 00:07 -0500
    Re: IDE or AHCI ? David Brown <david@westcontrol.removethisbit.com> - 2012-01-04 08:53 +0100
      Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-04 20:32 +1100
        Re: IDE or AHCI ? David Brown <david@westcontrol.removethisbit.com> - 2012-01-04 14:44 +0100
          Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 07:37 +1100
            Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-04 22:56 +0100
              Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 09:48 +1100
              Re: IDE or AHCI ? Ed Light <nobody@nobody.there> - 2012-01-04 21:40 -0800
              Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-05 05:37 +0000
                Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 17:37 +1100
      Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-04 09:29 -0500
        Re: IDE or AHCI ? David Brown <david@westcontrol.removethisbit.com> - 2012-01-04 16:04 +0100
          Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-04 19:19 +0000
            Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-04 23:14 +0100
              Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-05 08:47 +0000
          Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 07:51 +1100
        Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-04 19:16 +0000
        Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 07:41 +1100
          Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-05 14:44 -0500
            Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-06 17:35 +1100
              Re: IDE or AHCI ? Krypsis <krypsis@optusnet.com.au> - 2012-01-07 00:05 +1100
                Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-06 20:04 +0000
                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-06 21:13 +0000
                Re: IDE or AHCI ? cjt <cheljuba@prodigy.net> - 2012-01-06 20:42 -0600
                Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-07 13:48 +0100
                Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-07 14:09 +0000
                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-07 14:36 +0000
                Re: IDE or AHCI ? Krypsis <krypsis@optusnet.com.au> - 2012-01-08 02:11 +1100
                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-09 12:06 +0000
                Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-09 16:27 +0000
                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-09 17:36 +0000
                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-09 17:41 +0000
                Re: IDE or AHCI ? Winniethepooh@100acrewoods.net (GMAN) - 2012-01-09 19:07 +0000
                Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-09 20:12 +0100
                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-09 21:00 +0000
                Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 11:31 -0500
                Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-07 17:10 +0100
                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-10 14:18 +0000
                Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 11:23 -0500
                Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-09 16:30 +0000
                Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-09 20:16 +0100
                Re: IDE or AHCI ? cjt <cheljuba@prodigy.net> - 2012-01-09 17:13 -0600
                Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-07 08:11 +1100
                Re: IDE or AHCI ? Krypsis <krypsis@optusnet.com.au> - 2012-01-08 01:23 +1100
                Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-08 06:43 +1100
                Re: IDE or AHCI ? JW <none@dev.null> - 2012-01-09 05:23 -0500
              Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 10:24 -0500
                Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-10 09:34 +1100
                Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 20:04 -0500
                Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-10 15:33 +1100
            Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-06 09:48 +0000
              Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 11:35 -0500
                Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-09 20:23 +0100
                Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-10 11:31 +0000
                Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-20 06:54 -0500
      Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-04 19:14 +0000

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