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Ever heard of  AHCI ? No?

In short, AHCI is a new hardware communication standard from INTEL that can speed up hard drive operations and enable more efficient multitasking. Since the release of Vista, Windows has natively supported what is known as AHCI (Advanced Host controller Interface). In most cases Windows does not recognize the ability to use ACHI. Usually because it has not been switched on in your BIOS. If you have at least one SATA disk on your system you may benefit from activating the AHCI driver. Before we get to that part, let’s explore what the ACHI is and what it does.

What is AHCI ?

With all new technology, you get system improvements, new functionality, better speed, performance etc. To make Windows (or any system for that matter) communicate with your hardware, you need drivers. AHCI is the new set of drivers created to fully support the features of SATA-disks. AHCI allows software to communicate with Serial ATA (SATA) devices that are designed to offer features not offered by older hardware. But why care if your computer use IDE, PATA or AHCI drivers ?

The best argument I can give you is SPEED (Read more about performance; here, here and here). On AHCI enabled computers, read and write speed to and from your hard-drive(s) will be faster, the drives will be more quiet, and power consumption will decrease. As always there are pro’s and cons, and some experts claim that ACHI will actually slow down your system rather than improve it. But lets dwell on the improvements.

Native Command Queuing (NCQ)

NCQ let your hard-drive decide in which order to read and write the data transmitted to it. This allow your computer to get access to data that is stored in the same area on the disk before moving on to another part of the disk. This will of course reduce tear and ware on the reading head as it doesn’t have to jump as much back and forth, which in return reduce noise.

Imagine an elevator in a 100 storage building. There are three people in the elevator as you come in at the 4th floor. The floors 6, 30 and 75 has already been entered. You want to go to the 60th floor.  In which order should the elevator take you to your destination? in the order that the levels were selected, or in a sequential order ? Obviously the latter. Imagine having 10 people in that elevator bouncing up and down in a random order before getting to their floor. (Read more about NCQ here)

Hot plugging or hot swapping

It is always a good idea to power off your computer if you are adding or removing sensitive hardware. Mostly because it may destroy the hardware, and you risk loosing unsaved date. That being said, AHCI drivers have better support for the ability to add and remove devices to a computer while it is running and to let have the operating system automatically recognize the change. Devices in mind would be external ones, not the ones mounted inside your computer.

How to activate AHCI

First, let’s check if you already have AHCI installed, shall we ?

  • Open the Device Manager (Type “Device Manager” in the Start-menu search field)
  • Expand the IDE ATA/ATAPI Controller Section
  • Look for the driver named: “Standard AHCI 1.0 Serial ATA Controller
    If it’s not there, we need to activate it

Activating the AHCI Service

To make Windows Support AHCI it needs to be activated in your BIOS settings. And this is something you are supposed to do before, installing Windows. If you activate the AHCI support (in your BIOS) after installing Windows, chances are that your system will crash, or return numerous error messages when rebooting. To avoid this, we need to first activate the AHCI support in Windows, through the registry.

  • Open the registry editor (Type Regedit in the Start-menu search field).
  • Open the following key:
    HKEY_LOCAL_MACHINE | System | CurrentControlSet | Services | Msahci
  • Locate the key named START in the right panel
  • Set the Value to 0 (zero)
  • Close the Registry Editor

Now, you may shut down your computer and reboot into the  BIOS settings (usually F2 or DEL). Where to change the setting, differs from vendor to vendor, so you might want to consult your user manual or poke around in the settings menus to find it. Once located and activated, Save and reboot your computer (F10).

Upon Reboot Windows will install the appropriate driver. Check your Device Manager to confirm. You might need to reboot once more to activate the driver, but your computer should be ready for speed.


  • ExpertTester
  • Wikipedia (AHCI)
  • Wikipedia (NCQ)


About Thomas

Computer geek from the age of 7, which amounts to 30 years of computer experience. From the early days (when every computer company had their own OS) of DOS, Windows 1.0 through Seven...

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6 thoughts on “Enable Advanced Host Controller Interface (AHCI) in Windows 7 [How To]”

  1. Anderson Gosselen says:

    Cool! ;)

  2. Fayez Ahmed Khan Noman says:

    I have w7 64Bit Pro+ core i 7 2.8 GHz+ Gigabyte GA P55 USB 3.0 Mobo+ 4GB RAM. I have change my HDD yesterday 500GB 7200rpm to 2TB 5400rpm. Clone the drive through Paragon Drive Copy 11 without windows installation. And now running new 2TB and remove the 500GB from the system. I have AHCI enable and Intel Rapid Storage Technology installed with iRST soft. The problem is (IE9 + Opera) is (contuniuously Crashing + hang when start + Delayed start).. and quite slow down the pc. What could be the problem is?

    1. Bjhjh2 says:

      try reinstalling opera 

  3. Thomas says:

    @bdff9a6cfd6658aa8f5ad770b036f389:disqus You can read about benchmark tests done before and after installing AHCI if you follow the link to ExpertTester in the article.

  4. Microli says:

     Jinarion and Thomas, thanks for the suggestions! I forgot about the performance test in Win7.  I used a little benchmark program call CrystalDiskMark from LiberKey Tools (a great set btw) and it did show some disk improvements when AHCI was enabled. However performance test in Win7 didn’t make a difference whether AHCI is turned on or off.

    1. Rich says:

      Thanks for sharing your results Microli

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