AHCI vs IDE – Benchmark & Advantage

Posted: July 24, 2008 in Hardware
Tags: , , , ,

Recently, more and more user start to notice (note : not enthausiast) their main board or notebook has AHCI, instead of IDE (or legacy IDE). Most of us already aware what is IDE but what the heck is AHCI? What advantage could be gain from AHCI? Is AHCI is future thing of good old IDE interface. Will it slow down my system? Will it conflict my system?

What is AHCI ?

AHCI stand for Advance Host Controller Interface. AHCI is a hardware mechanism that allows software to communicate with Serial ATA (SATA) devices (such as host bus adapters) that are designed to offer features not offered by Parallel ATA (PATA) controllers, such as hot-plugging and native command queuing (NCQ). The specification details a system memory structure for computer hardware vendors in order to transfer data between system memory and the device.

Many SATA controllers can enable AHCI either separately or in conjunction with RAID support. Intel recommends choosing RAID mode on their motherboards (which also enables AHCI) rather than the plain AHCI/SATA mode for maximum flexibility, due to the issues caused when the mode is switched once an operating system has already been installed.

AHCI is fully supported out of the box for Microsoft Windows Vista and the Linux operating system from kernel 2.6.19. NetBSD also supports drivers in AHCI mode out of the box in certain versions. Older operating systems require drivers written by the host bus adapter vendor in order to support AHCI.

Advantage of AHCI

  1. Hot-Plugging (will not cover here as it will not affect computer performance)
  2. Native Command Queuing (might improve computer/system/hard disk responsiveness, espcially in multi-tasking environment

Will it slow down my computer

Several websites claim, NCQ (one of AHCI component) will cause performance degradation in single threaded benchmark, but other author claim otherwise. Let put our think hat here.

Their claims might correct at certain extent, but it is hard to prove that those single threaded benchmark will reflect real world application. Nowadays, hard disk is the slowest component in any modern PC (except we are using SSD). Antivirus, firewall, anti-spyware, windows update, background defragmentation, indexing (search), user applications (firefox, word, media player) ; all contribute to super multi-tasking, which I believe NCQ (AHCI) will show it advantage. So, in order to have better understanding on how NCQ (AHCI) could improve system responsiveness, let see what is NCQ actually is.

So, what is NCQ?

In principle, Native Command Queuing is relatively simple. It allows the drive to execute write /read commands that are transmitted randomly in order to optimise the movement of the reading head.

Speed is increased but there is also an impact on power consumption and noise level which is reduced. Of course, applications don’t have to work simultaneously and don’t have to wait for the previous result to send the next command. This of course isn’t always possible. Another possibility in using NCQ is multitasking in the case where you run two very heavy applications simultaneously from the drive point of view.

To better explain this situation, imagine an elevator, in which two people enter simultaneously on the ground floor. The first pushes the 12th floor button and the second the 2nd floor. It would be counterproductive to go to the 12th floor and then to the 2nd floor. The principle of NCQ was already in the ATA norm since 1997 with TCQ (Tagged Command Queuing). This heavier protocol could sometimes lead to significant performance losses in the case of low loads (no or very little command reorganisation to do) and has been integrated in a limited number of controllers. Hitachi supports it on 7K250 drives, like Western and the Raptor WD740GD, while on the chipset side, we can count on NVIDIA but not Intel.

SATA 3.0 Gbits /s defines a new speed of data transmission for the Serial ATA interface. Initially, SATA reached up to 1.5 Gbits /s, which really corresponds to 150 mega-octets per second as 20% of information is dedicated to error correction. The transfer rate is now increased to 300 MB/s but we have to keep in mind that this is the interface speed. It has nothing to do with disc speed alone. At most, cache speed would be affected.

For NCQ to be enabled, it must be supported and turned on in the SATA host bus adapter and in the hard drive itself. The appropriate driver must be loaded into the operating system to enable NCQ on the host bus adapter. Many newer chipsets support the Advanced Host Controller Interface (AHCI), which should allow a generic driver supplied by the operating system to control them and enable NCQ. In fact, newer mainstream Linux kernels support AHCI natively. Unfortunately, Windows XP requires the installation of a vendor-specific driver even if AHCI is present on the host bus adapter. Windows Vista corrects this situation by including a generic AHCI driver.

Benchmark Time J

Note : Intel and nVidia Standard mean these hard disk were benchmark using Intel and nVidia chipset without AHCI technology. Intel AHCI and nVidia Driver mean these hard disk were benchmark with AHCI turned on.

We start with a performance index based on figures obtained with the « XP Startup », « Application Loading » and « General Usage » profiles of PC Mark 2005.

The first thing to notice is that all drives benefit from the change to AHCI or the installation of NVIDIA’s driver. These two parameters allow the activation of NCQ…even for Western drives that do not support this functionality! With Intel’s platform, the most important gains due to AHCI are noted with the Samsung, Maxtor and Seagate drives. With NVIDIA it’s mainly the Raptor 150 GB and Samsung. For Maxtor and Hitachi, however, they are just noticeable.

If you focus just on drive performances, the Western SE16 dominates followed by Hitachi. Seagate ends up last behind Samsung.

Perfs – file copy

Performances – file copying

The next test is file copying. We measured reading, writing, and also the copy of the following files on hard drives: 2 big files for a total of 4.4 GB, plus 2620 files which total 2 GB, and finally 16046 files which weighs 733 MB. The source or target for reading or writing on the disc are two Raptor 74 GB in RAID which are capable of ensuring a transfer rate of 110 MB/s without restrictions.

This type of information is uninteresting of course because if the sequential transfer rate gives an idea of performances during the copy of big files, things will be different with small files. We copied the files in two different ways: whiting the same partition in the beginning of the disc and from this partition to a second one that begins at the middle of the disc.

First surprise, for unknown reasons the activation of AHCI on the installation of NVIDIA drivers notably reduces some of the reading performances: it is the case of the Raptor 150 GB in AHCI and the Seagate and Maxtor drives with NVIDIA’s drivers. These two use Agere controllers. Only the Western SE/SE16 really benefit from the modification which is in fact the installation of NVIDIA’s drivers. Except for these cases we noted that the Maxtor and Samsung provide the best transfer rates here whereas Western and Seagate are the slowest.

For writing however, AHCI/Driver NVIDIA gains are significant except for Seagate and Hitachi’s drive with NVIDIA’s platform. We noted the excellent performances of Samsung’s drive and the opposite for the Maxtor, which was really good for reading. Fortunately, gains obtained by the AHCI and NVIDIA’s drivers for this disc compensate for this.

Whether it’s for close or far copy, one drive is here very surprising when used with an AHCI controller. The Samsung drive is much faster than a Raptor and 30% ahead of the closest 7200 Rpm competitor. We made several tests to confirm these results and we always obtained the same figures. The other surprise was the performance drop recorded on the Maxtor with NVIDIA’s drivers. We also noted that a better access time doesn’t guaranty better performances for extended copies, because Hitachi’s performance reduction is more significant with a close copy than other discs. Except for Samsung and the Raptor, it’s the Western SE16 which is the fastest here.

Perfs – IOmeter per platform

Performances – IOmeter per platform

IOMeter is used to simulate a load in a multi-user environment. It’s a load type file server comprised of 80% reading and 20% writing, which is 100% randomly accessed on the disc. In this case, the NCQ can be particularly useful. We tested the IOMeter with a number of concurrent commands from 1 to 128 and of course for a single command, the NCQ doesn’t bring any improvements. The performance gap with the Raptor is much more significant, because this drive is particularly well suited to this type of use.

As the volume of data is rather significant we decided to represent it first per platform then below per drive with and without activation of the AAM on Intel’s platform.

For Intel and without AHCI, Western drives are ahead whatever the number of simultaneous accesses. Seagate is very close but loses ground beyond 16 accesses, even though the Hitachi and Samsung are relatively close. The Maxtor’s performances are clearly lower, however, despite a gap that tends to diminish as the load increases.

The activation of AHCI changes things. The Maxtor drive sees its performances increasing from 2 concurrent accesses to come in first (except of course for the Raptor). Maxtor can say thank you to NCQ. If Seagate also benefits from the NCQ, it isn’t really the case for Hitachi. Of course, it doesn’t change the Western SE/S16’s performances, because it simply doesn’t support this function. However, this doesn’t prevent them from reaching very high performances.

Without NVIDIA’s drivers, performances with NVIDIA’s platform are relatively similar to those obtained with Intel.

With NVIDIA’s drivers, the situation is different, because the NCQ really seems to work with 8 concurrent accesses and above. This is quite a lot and it doesn’t often happen in the case of a single user. Maxtor’s drive is strongly impacted even if it doesn’t stop it from being in the lead with 128 accesses (5% faster than with Intel’s platform).

Perfs – IOmeter per disc & AAM

Performances – IOMeter per drive & AAM

Here are now performances obtained per disc. In addition we added results obtained with AAM (Automatic Acoustic Management) activated on Intel’s platform.

For Hitachi, the NCQ doesn’t bring much whether it’s on an NVIDIA or Intel platform. We noted that with this type of access the AAM strongly reduces performances. The gap tends to reduce with the increase in number of simultaneous accesses.

We noticed with Maxtor’s drive that if NCQ based performance gains are visible from the start on the Intel platform, they only appear beyond 8 concurrent accesses on the nForce. It then immediately catches up and even results are even better. It’s rather unfortunate however, because in practice this type of drive will be of use for personal computers or with a limited amount of concurrent accesses. Here we can easily see the benefit of the NCQ to counter the negative effect of the AAM as from 4 simultaneous accesses the NCQ compensates completely.

Like with Samsung’s drive it is only from 16 concurrent accesses that the interest of NCQ is noticeable. Performances from this figure are much higher however than the one obtained with Intel’s platform. We noted that the activation of AAM leads to less significant performance reductions than with the Hitachi or Maxtor in this area.

With Seagate’s drive it isn’t possible to activate the AAM, which isn’t too critical. Once again, we have to wait until more than 8 accesses for the nForce NCQ to bring performance gains.

NCQ isn’t on the two Western drives and this is the reason why performances are similar between NVIDIA and Intel with or without AHCI / Driver. Once more we noted that even without NCQ, the gap due to the AAM tends to diminish with the increase of the number of concurrent accesses.

Here now is the Raptor 150 GB, which is in a totally different league except for NVIDIA’s NCQ performances.

Perfs – Perfs index & files with AAM

Performances – Applicative index & file copy with AAM

If performances with the IOMeter are strongly affected by AAM activation (because of the 100% random nature of disc accesses) we should take a look at the level of performances in less extreme situations.

As you can see, the performance drop is almost invisible on the Hitachi and isn’t huge on the Maxtor and Samsung. It’s greater for Western Digital. The Seagate 7200.10 doesn’t allow the user to modify the noise level whereas its adjustment with the Raptor doesn’t change anything.

We could have expected such a result. Whether it’s with reading or writing, performances don’t change much with or without noise management as heads don’t have to move a lot.

For copying the performance loss is notable for some of the discs such as the Western and slightly so with the Samsung. Hitachi and Maxtor’s performances remain almost unchanged. At times we even recorded a slight performance increase but this is most likely a testing error.

Warning (Potential Problem with AHCI)

Common problems switching to AHCI under Windows :

  • Enabling AHCI in a system BIOS will cause a 0x7B Blue Screen of Death STOP error (INACCESSIBLE_BOOT_DEVICE) on installations of Windows XP where AHCI/RAID drivers for that system’s chipset are not installed. Switching to AHCI mode requires installing new drivers before changing the BIOS settings.
  • For Intel chipsets (for example, Intel ICH9) drivers are available from either an OEM board or computer manufacturer. For the Intel versions, the driver must be loaded before loading the OS (by pressing F6 as setup starts).The Intel drivers will work for both XP and Vista. Also, in the case of ICH9, an unsupported method to enable AHCI on ICH9 is available.
  • When attempting to install Microsoft Windows XP or a previous version on an AHCI-enabled system will cause the setup to fail with the error message “set up could not detect hard disk drive…”. This problem can only be corrected by either using a floppy disk with the appropriate drivers, by slipstreaming the appropriate drivers into the Windows XP installation CD or by turning on IDE emulation in the BIOS settings if available (usually called as COMPATABILITY or ACPI).
  • Enabling AHCI in a system BIOS with Windows Vista already installed will result in a BSoD if SATA has been running in IDE mode during Vista’s installation. Before enabling AHCI in the BIOS, users must first follow the instructions found at Microsoft Knowledge Base article 922976.
  • Enabling AHCI in a system BIOS on installations of Windows XP or Windows Vista will cause SATA Optical drives to disappear. A Hotfix for Windows Vista is available under the title: “SATA optical drives are not available after you start a Windows Vista-based computer.” This problem is also fixed in Vista SP1.

Common problems switching to AHCI under Linux :

  • AHCI controller does not work on AMD/ATI RS400-200 and RS480 HBA when MSI is enabled due to a hardware error. In order for AHCI to work users must provide the “pci=nomsi” kernel boot parameter. With MSI disabled in this way, the PCIe bus can only act as a faster PCI bus with hotplug capabilities. This is also true of the Nvidia nForce 560 chipset.
  • AHCI controller on AMD/ATI SB600 HBA can’t do 64-bit DMA transfers. 64-bit addressing is optional in AHCI 1.1 and the chip claims it can do them, but in reality it can’t, so it is disabled. After that it will be forced to do 32-bit DMA transfers. Thus DMA transfers will occur in the lower 4 GiB region of the memory, and bounce buffers must be used sometimes if there is more than 4 GiB of RAM.

Verdict :

These extensive benchmarks clearly show to us, AHCI (NCQ) definitely could improve computer system responsiveness, transfer rate, number of IO per second and the list goes on. Enough to say, it will make your hard disk more efficient (and indirectly reduce it wear and tear). Notice that, not every hard disk with NCQ turn on could provide positive performance gain at every single benchmark. I believe this phenomenon explain why certain author claim NCQ improve their benchmark score while others don’t.

As for Acer 4530, I realize, AHCI or NCQ improve my system (Vista) responsiveness espcially when I am using VMWare Server (with 2 Suse Linux Enterprise Guest System running on top). Background activity such as anti-virus, spyware, defrag or event torrenting seem lighter than before (IDE). For the record, my Acer 4530 use Seagate SATA 300 with NCQ mobile hard disk.

My personal recommendation, turn on AHCI if your system permit you to do so. For Vista user, you can turn AHCI support without reformat your system. What you need to do is, enable Vista standard AHCI driver (provided you install Vista in IDE mode, so AHCI driver is not activated) using regedit. Detail : Read Here

Credit : Wikipedia, BeHardware.com, Me

Comments
  1. Neel says:

    Excellent article. This contains everything I wanted to know about it.

    Thank You very much.

  2. expertester says:

    No problem Neel…

    I was in the same shoes as yours..wondering about AHCI before.

  3. Paul says:

    Good article; decided to give AHCI a try with my new build; Gigabyte GA-P35-DS3L (ICH9E southbridge) and a Samsung F1 hd753lj 750Gb SATA(3.0Gb/s). Downloaded the latest Intel Matrix Storage Manager; extracted the AHCI drivers to a floppy; set AHCI mode in the BIOS; booted from a slipstreamed WinXP Pro SP3 CD and did the F6 controller pre installation from floppy; selected the right controller; setup continues from CD, but ends installation the next stage with the “Unable to detect harddisk” message as the Windows XP setup installation interface does not detect and recognize any of the hard disks mounted on S-ATA (Serial ATA) ports, and thus XP installer cannot find usable physical disks on the computer system and unable to continue to install XP, forcing me to quit by pressing F3.

  4. expertester says:

    Paul :
    If your windows XP cant detect hdd under AHCI, it mean, your driver is not correct. If you already slipstream it using nLite, there is no need for F6 floppy. It is either one…

    Since you got floppy drive, you may need to check with your mobo manufacturer AHCI driver for the correct one…and directly load the driver from F6…to test which one work for you.

  5. Normal User says:

    Good article; I was also unsure about advantages by changing from IDE to AHCI.
    By the way, I found in internet a very simple way to change BIOS from IDE to AHCI without new XP-Installation and it works!
    1- Go to hardware manager, click on “Intel(R)…ATA- Storage controller” that you are using with IDE and with a right maus click, driver update.
    Look for and load the right AHCI driver for your chipset.
    Turn off XP and go to Bios set-up wenn re-booting, change Bios to AHCI. Re-boot.
    XP will start, recognize new Hardware and akst to re-boot. Just do it.
    XP boot normally. Done. It worked for me, but do it on your own risk.
    After doing it, I was wondering why experts doesn’t suggest it. Maybe to sell floppy drivers?

  6. [...] people’s results on this…next time I do a reformat I think I’m going to enable ACHI on my system AHCI vs IDE ? Benchmark & Advantage Expertester __________________ ASUS Maximus Formula (X38) ***** EVGA 8800GT Superclocked 512MB Intel E8400 [...]

  7. Your regular guy says:

    Thank you very much for this comprehensive article. It was very useful.

  8. expertester says:

    you are welcome ^^

  9. [...] In plus, sub AHCI ai si hot swap. Iaca (pentru maniacii care n-au altceva mai bun de facut): http://expertester.wordpress.com/200…ark-advantage/ __________________ There is no one who would have me – I can’t cook. Last edited by stiller; [...]

  10. [...] or 3, I would use it there as well. I initially added it to my present Vista build as a guess, but http://expertester.wordpress.com/200…ark-advantage/ suggests there may be validity, and in any case, the only time it "hurts" me is when I go [...]

  11. Vincent says:

    Expertester, I have to say that this is a really stunning article you posted here!
    Out of most of the sites I have seen this rates as the top! I take my hat off to you as this is the type of article that one should have in the web and if only others could follow your example, it would make life so much easier for every body.

    Well done!!!!!!!!!!

  12. Skat Barnett says:

    Articles like this make the internet invaluable

    free knowledge !!!!!! thanks !!!!!!!!

    – New Zealand

  13. Matt says:

    Excellent article! One thing to note, for those who enable AHCI, you’ll need that driver floppy disk handy to install XP. If you’re like me and don’t have a floppy drive, or just really hate to use them, check out http://www.nliteos.com. N’lite is a program written to allow you to slipstream drivers onto your XP CD. It has saved me lots of times.

  14. Mick says:

    Excellent review!… I’ve changed to AHCI some time ago and it seems to improve my overall performance. No BSoD yet… I made an AHCI fix (in a Exe file) that made the changes on the system and install the drivers … it works this way:
    while the system is still in IDE mode in winxp:
    Run the exe..
    next .. next…. reboot… change BIOS sata to AHCI. when reboot, drivers will install, and ask for reboot again… and that’s it!… AHCI Ready without problems!…
    if Anybody wants my fix, just ask for it to my mail “mick2005 at gmail”, and i be please to provide it… =)

    Note:. uses Intel Matrix Storage (8.7.0.1007) for ICH9 (it works in all latest intel chipsets…i guess )

    Greetings

  15. Nicu says:

    Wow! This article was more than I expected. Actually, it was more than I could read at this time of the morning but I managed to draw the line and make a conclusion using the information in here. Thank you very much! :)

    Bookmarked!

  16. Doug says:

    About to build with Gigabyte motherboard supporting AHCI but using Western Digital Black Caviar HDD and two SATA optical drives. Looks like if I use XP Pro I should not enable AHCI or I will lose the optical drive recognition in exchange for minimal performance gain.

  17. davidh5551 says:

    Great!! My Vostro 1500 is now the fastest machine in the house. The boot time is half of what it eas time with IDE. I just can’t believe such a simple process can make this hugh change on my vostro performance.
    Thanks!

  18. davidh5551 says:

    Great!! My Vostro 1500 is now the fastest machine in the house. The boot time is half of what it was with IDE. I just can’t believe such a simple process can make this hugh change on my vostro performance.
    Thanks!

  19. Trevor says:

    Thanks for the info on AHCI. It was helpful.

    The problem I have with AHCI is that using certain programs don’t work now, mainly utilities.
    Programs like Paragon Total Defrag which requires to boot your system and at boot up it goes to the windows logo screen and then black screen then a quick BSoD and reboots.

    Any suggestions on how to get around this. I’ve had the same issue using Acronis’s sofware.

  20. Nicu says:

    Trevor, I think you should address this issue to the software manufacturers. If I’m not wrong, it’s up to the software that boots-up to load the appropriate drivers. In this case, the software is the operating system itself.

    In these defrag tools’ cases, it looks like they are not using/loading the AHCI drivers so they crash the system. I’m 99,9% sure this is related to software issues in the defraggers, not the OS nor the AHCI drivers, that why you should report this to Paragon & Acronis.

    My only suggestion is to try the latest available versions of their software. If you already did that, I guess there’s nothing else to do except for sending them a bug report/missing feature letter.

    Maybe other defragmentation tools work with AHCI but I haven’t tried any yet. I can only say good luck with that! :)

  21. Osi says:

    Thank’s for the great info ;)

  22. Kenobi says:

    very well done, and the only comprehensive article about AHCI I’d really recommend.
    Thank you!

  23. Mick says:

    TREVOR… I had the same problem, but what i do when use boot-time apps.. is change the bios back to the IDE mode, make the changes you need and turn it back to AHCI…

    but is like NICU said.. it’s a software related issue.

    Note: once the fix has been aplied, you can boot XP in both (IDE & AHCI) modes.

  24. brunoz says:

    thanks for the article, cleared up a lot of things, great research work.

  25. expertester says:

    Thanks guys…glad it help.

  26. [...] expertester.wordpress.com [...]

  27. Richard says:

    Great article, it is apparent that you put a lot of time and effort into it.

    :: RAISES DRINK ::

  28. Trevor2 says:

    Great article, thanks.
    I just purchased an ASUS 1005HA with German XP installed and wanted to change to English. I inserted disk in external optical drive and quickly realised I could not install if I left AHCI enabled in the bios so I disabled it and enabled IDE and the installation ran smooth, all drivers OK and system is ok. When installing XP I also had to disable “fast boot” and as well as the “AHCI” in bios.
    Now my pc is running in IDE mode, my questions are; is it worth slip streaming XP with the original AHCI files I have and reinstalling everything again? Will I benefit?
    Is the system compromised if I leave it as it is? And can anyone point me in the right direction on how to slipstream the AHCI drivers with my existing XP?, Thanks, Trevor2

    • Mick says:

      You don’t need to reinstall all, to activate AHCI, just must install the service of the driver “iastor” (by changing windows registry), activate AHCI in BIOS, start winxp, and then install the Intel Matrix Storage software.

      I have a fix (setup utility) that make this changes, download Intel Software and patch the system to safe-boot into winxp with AHCI enabled.

      contact me if you want it.

      • changlee says:

        Hi
        How to donwload for linux case to change back from IDE to AHCI
        since redhat 4.8 does not have AHCI driver.
        I will install with IDE option then install AHCI driver, is it working??

        Thanks for your help!!
        Chang

  29. expertester says:

    If you need to slip stream and reinstall your fresh install windows, I believe it is totally not worth. The benefit is so insignificant. Mind you that you may get negative impact as well.

  30. [...] Re: Legacy IDE, Native IDE, AHCI and RAID?? Check this out. AHCI vs IDE – Benchmark & Advantage [...]

  31. [...] http://expertester.wordpress.com/200…ark-advantage/ ..a __________________ So you think hot air rises? Think again! ..a? Just how I sign my posts (Andy) Quote: [...]

  32. PALADiN says:

    I have a Samsung 750GB SATA drive. I’ve tried to enable AHCI in the BIOS of my mobo (Gigabyte EP45-DS3) but enabling it causes my computer to refuse to boot from my DVD drive (Pioneer DVR-216BK)

    Can someone help please?

  33. [...] Can't Boot to CD/DVD while AHCI is active (EP45-DS3) These benchmarks got me interested (I have a Samsung SATA drive). Apparently the DVD drive should always be on port [...]

  34. Alex says:

    great article ! Well done

  35. [...] your eSATA port. Most of the time AHCI will improve system performance. You can check out this great AHCI vs IDE test if you want specifics. This about sums it up….. [...]

  36. [...] AHCI enables NCQ (Native command queuing) and faster multi-tasking response. See this article describing why you should use AHCI [...]

  37. George says:

    Other than a lot of broken english, this is a pretty good article. Thanks.

  38. Kevin says:

    Although this thread is getting cold, there is one more thing to point out. Hot-swap has been mentioned for AHCI mode, but the term leads one to dismiss it as being irrelevant. Allow me to coin a new phrase, even if just for the moment:

    “it-just-died detection”

    Even without the intention to hot-swap a replacement in, the kernel level hot-swap support lets it notice when a disk has dropped off the system, whether by yanking its cable (bad admin!) or when it actually bites the dust.

    This is a bigger advantage when you’re running software mirroring, but I’d think it would also benefit secondary drives, by letting “ls” and friends fail gracefully, rather than hanging forever and forcing you to kill your terminal window.

  39. [...] Any advantages to going AHCI vs IDE mode? Any advantages worth a darn? Here is a good read: http://expertester.wordpress.com/200…ark-advantage/ The one advantage I like is hot-swapping of the SATA. __________________ [...]

  40. [...] since I didnt get any personal OCN members response I did some looking. http://expertester.wordpress.com/200…ark-advantage/ Its a bit old and if anyone here has any experience please post it. I will try this weekend when I [...]

  41. dan says:

    my optical drives (dvd, cd) not working now.
    how to solve this ?

    TIA :)

    * winxp pro with AHCI drivers

  42. Panchapakesan V Iyer says:

    Very informative.
    Not sure, what % of users would have actually make use of AHCI despite having the featured box.
    Good luck.

  43. [...] met ahci schijven loskoppelen zoals met een usb stick wel intel matrix storage driver installeren http://expertester.wordpress.com/200…ark-advantage/ —check in de bios eens je temperatuur, fan die stil staat processor overhit, ram eens [...]

  44. Bommetje says:

    Thanks, answered all my questions.
    I suppose the benchmarks are all for XP? Maybe you could mention a few times which OS was used for the benches.

  45. Taco says:

    Many thanks for such a great article. It was EXACTLY what I was looking for!

  46. e-berlin says:

    Great! Everything in one place. And a great blog theme.

  47. [...] setup and haven't encountered any problems, this site should help you decide whether you want it. http://expertester.wordpress.com/200…ark-advantage/ Yes, you have to set it in the BIOS. __________________ Join the Overclock.net Foldathon – up [...]

  48. [...] disk responsiveness, especially in multi-tasking environment You can read more about AHCI mode HERE Instruction: There is one way to fix this, although you need to have knowledge of registry [...]

  49. [...] – Benchmark AHCI vs IDE *2 – NCQ es una tecnología diseñada para incrementar el rendimiento en los discos duros SATA bajo [...]

  50. mt says:

    from Microsoft Support:

    Article ID: 922976 – Last Review: February 8, 2010 – Revision: 3.2
    Error message when you start a Windows 7 or Windows Vista-based computer after you change the SATA mode of the boot drive: “STOP 0x0000007B INACCESSABLE_BOOT_DEVICE”
    View products that this article applies to.
    Support for Windows Vista without any service packs installed ended on April 13, 2010. To continue receiving security updates for Windows, make sure you’re running Windows Vista with Service Pack 2 (SP2). For more information, refer to this Microsoft web page: Support is ending for some versions of Windows (http://windows.microsoft.com/en-us/windows/help/end-support-windows-xp-sp2-windows-vista-without-service-packs)
    Expand all | Collapse all
    SYMPTOMS
    Consider the following scenario. In the BIOS setup of a Microsoft Windows 7 or Windows Vista-based computer, you change the Serial Advanced Technology Attachment (SATA) mode of the boot drive to use the either Advanced Host Controller Interface (AHCI) specification or RAID features. You then restart the computer. In this scenario, you receive the following error message:
    STOP 0x0000007B INACCESSABLE_BOOT_DEVICE
    Back to the top
    CAUSE
    This issue occurs if the disk driver in Windows 7 and Windows Vista is disabled. This driver must be enabled before you change the SATA/RAID mode of the boot drive.
    Back to the top
    RESOLUTION
    Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
    322756 (http://support.microsoft.com/kb/322756/ ) How to back up and restore the registry in Windows
    To resolve this issue, enable the AHCI driver in the registry before you change the SATA mode of the boot drive. To do this, follow these steps:

    1. Exit all Windows-based programs.
    2. Click Start, type regedit in the Start Search box, and then press ENTER.
    3. If you receive the User Account Control dialog box, click Continue.
    4. Locate and then click one of the following registry subkeys:
    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
    5. In the right pane, right-click Start in the Name column, and then click Modify.
    6. In the Value data box, type 0, and then click OK.
    7. On the File menu, click Exit to close Registry Editor.

    Result:

    By following these steps to enable AHCI on my Win7 BIOS, still caused unbootable problem. Still had to return to AHCI “disabled” status to make windows bootable.

  51. Joe194B says:

    I know this is an old article but was a good read and answered my questions. thanks

  52. Great Article keep on with good job..

    Finnaly my achi DILEMMAS ARE GONE.

    Learned a lot from this article.

  53. Vaseem says:

    please help me any one
    does my mother board support AHCI it supports SATA hard disks
    my motherboard is D945GCNL

  54. Kedar says:

    Hi expertester,

    I must say this is one of the best articles i have read in recent times. too good…!!
    Sadly i read it after i ran into the BSoD :(
    my issue is resolved now…!!

  55. [...] var en firmware opdatering til disken. OCZ oplyser selv at de kraftigt anbefaler at disken kører i AHCI mode, og hvis man kørte IDE mode kunne man skifte, blot ved at ændre en setting i registry [...]

  56. ABU HASAN says:

    Amazing article!!!
    Never, I mean never read something so comprehnsive yet so easy to understand before… NEVER:)
    Thank you alot, now I know what to do with those options in BIOS setup, and I’m definitely enabling AHCI on my SATA drive.
    Thank you once again,

  57. DragonHammer says:

    Great Article. Just made the big step to AHCI, thanks to this wonderful guide! Nicely done, no problems whatsoever.

  58. Lynna says:

    I am glad this article was still around, I was attempting to explain this too a customer that is having some pretty nice PC’s built by our shop and attempting to explain this was not easy. He read this and got a better understanding of what we were trying to explain. Excellent work and info here. I know it is old but it is still great! Thank you again.

  59. [...] je dit niet doet krijg je inderdaad die foutmelding. Op zich maakt het best veel uit ja. Zie hier voor meer [...]

  60. gggirlgeek says:

    So, I wonder…. Ever since I installed Win7 my file transfers, especially to recycle bin have been slow. When I networked my XP machine to the Win7 machine the XP machine slowed down too. I confirmed this by booting Win7 machine into UBCD4win CD (BartPE) and testing transfers to recycle bin. Sure enough, fast as heck, even though the OS is on CD!

    Maybe AHCI would help? Hmmmm. Will report back.

  61. Tony says:

    I have always been wary about using AHCI because of various issues with third party apps. In situations where there is not conflicting software, i agree it is the better option to go with.

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  85. [...] disk responsiveness, especially in multi-tasking environment You can read more about AHCI mode HERE Instruction: There is one way to fix this, although you need to have knowledge of registry [...]

  86. [...] AHCI even affect the performance of an SSD? I just read http://expertester.wordpress.com/200…ark-advantage/ and all the references given indicated that it changed how HDD's function and read and write. [...]

  87. herry165 says:

    thank, this artikle help me a lot, i look positive side using ahci than ide, thank, and i think better using standart achi driver provided by win7 os, more faster.

  88. [...] Some hard drives actually benefit more from AHCI, others, not so much. http://expertester.wordpress.com/200…ark-advantage/ __________________ FOR SALE: XFX 4890s, Water cooling, Western Digital HDDs FOR SALE: Resident [...]

  89. SAURABH KUMAR says:

    who is better in ide and ahci.

  90. kneekoo says:

    AHCI is better. Why didn’t you read the article?

  91. menerc says:

    impressive article. Thanks a lot.

  92. Derek says:

    Thank you! Had to reset my BIOS and forgot the settings. Anything to consider in regards to Windows 7 or can ACHI easily be switched on and off without the issues in XP and earlier OS’s?

  93. Phil says:

    This excellent article still remains relevant.

    Interestingly upgrading the firmware on ADATA’s SSD drives requires the drive be accessible via ACHI.

    ADATA provide a .pdf with instructions on how to switch Windows 7 from IDE to ACHI via a registry edit followed by a bios change. The change was non-destructive and Windows 7 booted, installed some drivers and rebooted again. Then I was able to install the latest ADATA firmware which also required a couple of reboots. It was all done without any destruction of data.

    Apparently if you attempt the firmware upgrade in IDE mode the results are uncertain.

  94. [...] อ่านคุณสมบัติและความเร็วของ AHCI คลิ๊กที่นี่ [...]

  95. Diamond Pao says:

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  96. silviu says:

    hi man, i got this acer 5742g, the hdd is seted to AHCI. but my HDD freezez a lot like when im browsing or playing a game it freezes for 4-5 seconds every 2-6 minutes somethimes it freezes every 10 seconds like in FIFA 08…what happens if i try to reinstall windows on Hdd setted IDE? it really pisses me off

  97. [...] Untuk mengetahui lebih lengkap Hasil Benchmarknya dan lebih lengkap tentang apakah AHCI itu, klik: http://expertester.wordpress.com Berikut adalah cara mengubah dari IDE ke AHCI, Dikutip dari [...]

  98. [...] Untuk mengetahui lebih lengkap Hasil Benchmarknya dan lebih lengkap tentang apakah AHCI itu, klik: http://expertester.wordpress.com Berikut adalah cara mengubah dari IDE ke AHCI, Dikutip dari [...]

  99. [...] var en firmware opdatering til disken. OCZ oplyser selv at de kraftigt anbefaler at disken kører i AHCI mode, og hvis man kørte IDE mode kunne man skifte, blot ved at ændre en setting i registry [...]

  100. Jerry2k4 says:

    THnks a lot now i know!

  101. [...] was better for fast IO which could be a gaming upgrade all by itself if it is not already enabled. AHCI vs IDE Reply With Quote   [...]

  102. robin says:

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  103. [...] AHCI vs IDE – Benchmark & Advantage @ Expertester [...]

    • Yaser says:

      Hey Techies…

      I need some information regarding the convertion of IDE to AHCI.

      I have built a new PC with i5 2500K,Asus P8Z77 M Pro Motherboard and 8GB Transcend RAM.

      I tried to install Windows 7 ultimate after formatting my old hard disk(Segate Bracuda 500 GB).I got an error as “Enable Host Controller in BIOS settings”

      I don’t aware that AHCI was default SATA configuration in my Motherboard.

      Then i surfed and found that this is the issue with IDE to AHCI Conversion.

      I also found a Microsoft KB Error message when you start a Windows 7 or Windows Vista-based computer after you change the SATA mode of the boot drive: “STOP 0x0000007B INACCESSABLE_BOOT_DEVICE”. The KB has a Auto fix setup file that can be installed on a pre installed(OS) hard disk. But i have formatted my disk and i couldn’t install a new copy of windows 7.

      There is an auto run files for the same Auto Fix but when i tried to boot the auto fix from a USB stick,i got an error “Please insert Floppy Disk for copying files”.

      I dont have a floppy drive attached to my new computer.

      I have a solution..Can you guys confirm me whether it will work or not?

      let me connect it to my old computer(intel dual core with mercury motherboard) and install window7 in it with the Auto fix installed on it and if i connect it to my new computer and boot it will it be working?Is IDE will be converted to AHCI after doing this?

      Can any one tell me..?I m totally fed up with this AHCI

      Thanks in advance for your jiffy solutions!!

  104. expertester says:

    sorry about the utterly useless spam and comments guys. Due to that reason, I turn off the comment function for this post.

    PS: Windows XP was used for while conducting those benchmark.

  105. [...] any reply for sometime before I could figure it out. I could see that ATA driver has API-s to get AHCI status at the kernel level but couldn’t find anything that would give the status at user [...]

  106. [...] Voici un article, en anglais dans le texte, qui explique le gain pour vos actions courantes, grâce à la modification d’IDE en AHCI dans votre bios. ICI [...]

  107. […] Nach allem was ich bisher gesehen habe bewegt sich der Vorteil im einstelligen Prozentbereich (z.B. AHCI vs IDE), sofern man nicht mehrfach auf die Festplatte zugreift, er kopiert ja von einer anderen Festplatte […]

  108. […] Hoi Kurtt, Heb even gekeken op site van Asus en er zijn AHCI drivers voorhanden voor je moederbord dus zal deze dit ook ondersteunen. De info die je gevonden hebt klopt en hier staat het beschreven op het OCZ forum. Hier vind je enkel test met het verschil tussen IDE en AHCI AHCI vs IDE ? Benchmark & Advantage | Expertester […]

  109. […] AHCI Controller Support which enables Mac OS guests to use IDE CDROM drives. AHCI is an operating mode for SATA.  More info on ahci here. […]