If you turn to the system administrator and ask a question, what is the weakest link in the computer? - you will receive the answer that it is the HDD, because it is practically the only mechanical element of the system that slows down the operation of the entire computer. In this regard, many manufacturers were looking for a way out, at least some opportunity to speed it up, also with SSDs. The output became visible when using AHCI.

AHCI disk mode includes several main differences (there are 3 of them), which make it a priority in the use of all disk drives, except outdated IDEs. The main features of the mode:

• Hot Plug – allows you to “hot” change computer components (disks). Thus, there is no need to turn off and unplug the PC; you can change the HDD and SSD directly in operating mode. This is important for server stations where disconnection is unacceptable and is simply convenient for anyone who uses multiple disks;
• NCQ – support for “deep” command sequence, that is, it is able to configure a more efficient trajectory of the head in mechanical ones and significantly increases the output in SSDs;

• TRIM is primarily applicable to SSDs, as it guarantees a significant increase in speed.

AHCI mode allows you to enjoy all these benefits and most likely you have the opportunity to enable it. If you are using an SSD, then you probably need to turn it on to see the proper speed of its operation, this applies to both SATA II and SATA III, except for older IDE drives. Therefore, if you are in doubt about which mode to choose: ide or AHCI, the latter is definitely an advantage.

How to check if AHCI mode is enabled?

The first thing you need to do is find out whether it is worth pursuing further switching; perhaps it is already active for you. There are several places that show the information you need: Device Manager and BIOS.

• Click Start, right click on “Computer” and click on “Properties”;
• Now select "Device Manager";

• Next, expand the “IDE ATA/ATAPI controllers” section;
• Check to see if there is a section called AHCI.

If there is no such item, you may find out that it is inactive. We will also consider another option through the BIOS (UEFI):

• Go to the BIOS by pressing Del or F2 (possibly other keys) when starting the computer;
• You should go to the section called SATA or Storage in different options until you find SATA Mode/Configuration, where the mode will be shown.

At this stage, do not change the connection mode, as this may result in system errors. It is best to enable AHCI mode in the BIOS and install on a new Windows, which guarantees normal processing of the mode, but this is quite radical.

How to enable AHCI mode in Windows 7?

The most relevant and widespread system in which we will perform actions. It's also worth noting that if you're installing a new drive, you can freely switch the AHCI mode without any consequences. There are also several options for activating AHCI: through the registry and through a utility. A more correct option would be to use the registry to prepare the system for further changes; the latter method will simply help solve pending errors in the computer.

• Press Win + R and type regedit;
• Follow HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci;
• Replace the value of the Start option with 0;

• Here you will find the lastorV section;
• Also replace Start with 0.

Now you can enable AHCI mode in the BIOS and Windows will correctly detect it by installing the necessary drivers. An alternative method involves changing the mode initially and then simply clearing the error. To do this, use the official Microsoft Fix it utility. After installation, run a check and the failures will be eliminated; you may need to run from safe mode.

How to enable AHCI mode in Windows 10?

In general, the actions are not significantly different; let’s look at the differences in editing the registry.

• In the same section as in Windows 7, you need to change the Start parameters in the iaStorV and storahci folders to the value 0;
• Expand each of the specified sections and go to the StartOverride subsections, where parameter 0 is set to 0.

We were able to enable AHCI Windows mode, but it is worth noting that it is better to launch it for the first time in safe mode in order to avoid unnecessary problems. During the initial startup, the AHCI operating mode will install the necessary drivers automatically.

It is worth mentioning the distinctive features of how to enable AHCI mode in Windows XP and other outdated versions.

Despite the fact that XP does not support this mode at all, there are drivers that expand these capabilities, although this is unsafe.

You should also think about whether it is worth it, because if the computer is very weak for more modern systems, then the speed increase will be insignificant. Also, the AHCI controller mode in Vista is activated in the same way as the “seven”.

So, AHCI sata mode is easy to enable, and the system will reward you for your efforts with an increase in speed. Usually there are no problems with changing the controller, but if you encounter them, just run the Microsoft Fix it utility. AHCI is required when using an SSD drive, otherwise you will not use its full speed.

If you still have questions on the topic “What is AHCI mode and how to configure it?”, you can ask them in the comments

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AHCI mode is supported in Windows operating systems starting from Windows Vista. In older versions of the OS (such as Windows XP, etc.), there is no built-in support for AHCI mode and for this mode to work, you must install additional vendor-specific drivers.

However, not everything was smooth with the activation of AHCI mode in the new Microsoft operating systems. If the system was installed in normal (IDE) mode, the AHCI driver in the system is located in disabled condition. This leads to the fact that on such systems, when AHCI mode is enabled on a SATA controller in the BIOS, the system stops seeing the sata drive (the necessary ahci driver is missing) and crashes into BSOD ( INACCESSIBLE_BOOT_DEVICE). For this reason, controller chipset manufacturers (primarily Intel) recommend enabling AHCI mode BEFORE OS installation, in this case the installer understands that the chipset supports AHCI mode and installs the necessary drivers (for some chipsets, it is sometimes necessary to load specific AHCI/RAID drivers directly during the Windows installation process, for example, from a USB flash drive or CD/DVD drive).

Note. Mode AHCI (Advance Host Controller Interface) Enables advanced SATA features such as hot plugging ( Hot-Plugging) And NCQ(native command queuing), which improves the performance of disk operations.

In Windows 8, the situation with activating AHCI has not changed, and if you try to change the SATA controller mode to AHCI without making changes to Windows itself, this will lead to the inability to boot from the system disk. The fact is that Windows 8 also does not automatically load the AHCI driver for a controller that was not in AHCI mode at the time the system was installed.

The article is intended for those who installed Windows 8 in IDE mode and would like to switch to AHCI mode without reinstalling the operating system. If the BIOS (or) is already set to AHCI mode, then there is no need to do anything additional - your Windows 8 already supports AHCI mode.

We have already described without reinstallation. According to this article, on Windows 7 running in normal (ide) mode, you need to switch the standard AHCI driver to automatic loading mode (the driver is called msahci) and only then activate AHCI in the BIOS. The procedure went quite smoothly and in the vast majority of cases painless.

In Windows 8 (and Windows Server 2012), when trying to enable AHCI mode in this way, the user will encounter a problem: the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci branch is simply missing in the registry. And trying to create it manually will lead to nothing.

The fact is that Microsoft decided to change the name of the driver responsible for supporting AHCI mode for SATA controllers, replacing it with a new driver called StorAHCI. It is worth noting that this driver has the same functionality and supports the same devices as MSAHCI.

We were able to discover two ways to activate AHCI after installing Windows 8. One of which is associated with modifying the registry, the second is with booting in safe mode.

Enable AHCI in Windows 8 using the registry

To enable AHCI mode in Windows 8 without reinstalling the system (which was installed in IDE mode), you need to make changes to the system registry.

Note: once again we remind you that the specified modification of the Windows 8 registry must be done BEFORE enabling AHCI in BIOS.

Unfortunately, the specified method for activating the ahci driver in Windows 8 does not always work (it does not work in about 10-20% of cases). In this case, it is recommended to use the official instructions from Microsoft, available in the knowledge base article KB2751461(http://support.microsoft.com/kb/2751461).

An alternative way to enable AHCI in Windows 8

In the event that the above method did not work, and Windows 8 does not boot in AHCI mode, going into BSOD or endless attempts to restore Windows (Attempting repair). Necessary

1. Disable AHCI mode in BIOS
2. Undo changes to the system registry by setting ErrorControl = 3 And StartOverride\0 = 3
3. Using the following command, we will set Windows 8 to boot in safe mode - Safe Mode (as an option, you can). bcdedit /set (current) safeboot minimal
4. Then you need to reboot the system, enter the BIOS again, switch to AHCI Mode and save the changes.
5. As a result, Windows 8 should boot into safe mode and automatically install the AHCI driver.
6. Then you need to disable booting in SafeMode: bcdedit /deletevalue (current) safeboot
7. And restart Windows
8. The next time you boot the system, the system should boot normally. It remains to make sure that the AHCI controller appears in the device manager.

To make sure that the performance of the Windows 8 disk subsystem has increased due to AHCI mode, run the update and check that the Disk data transfer rate has increased. In our example from 5.2 to 8.1 units (although to be frank there are more 🙂).

One of the main elements of any computer device, as you know, is the hard drive on which information is stored. In relation to hard drives of any type, the term AHCI is used. But many users not only know how to enable AHCI, but have no idea what it is. Let's consider the meaning of the main term and the actions required to activate this mode on Windows systems.

What is AHCI?

Modern hard drives connected to the motherboard through operation can use two modes: IDE (compatibility with legacy equipment) and AHCI - the latest standard, designated as Advanced Host Controller Interface, which allows you to significantly increase the performance of the device itself and the installed operating system due to faster reading data.

Almost all modern SSD drives show an increase in performance when accessing them precisely when the AHCI mode is set. But this is not the most important thing.

What is AHCI mode for?

Let's leave for now the question of how to enable AHCI mode in Windows, and let's look at the benefits that a user of a modern computer can derive from activating this mode.

First of all, when AHCI mode is activated, you can change or install additional hard drives, as they say, “on the fly” (even without turning off the computer or reinstalling the operating system). This is undoubtedly a huge plus for servers.

The second aspect is related to the fact that when this mode is installed, a special NCQ technology comes into effect, which allows you to reduce the number of movements of the read heads, while speeding up the simultaneous use of access to the hard drive by different applications, programs and services. Finally, activating AHCI is believed to have a beneficial effect on overall system performance. Of course, as evidenced by reviews from experts and users, at home there will not be a significant increase in performance, however, if you install an SSD hard drive, it is still better to enable this mode.

What not to do and what to pay attention to initially

But the most important misconception of most users is that they try to use exclusively the settings of the primary BIOS system for activation (at least, this can be read in most reviews of emerging problems). It is strictly forbidden to do this without performing preliminary actions in the operating system.

You can activate the mode in the BIOS only if you install the OS on a “clean” hard drive. If you perform this procedure with an existing OS on board, Windows will generate an error at startup and go into constant reboot mode. Then the complaints begin, saying that the user enabled AHCI mode in Windows, but nothing good came of it. What to say? Basic rules may have been violated, since different modifications of the system require different actions.

How to check if AHCI mode is active?

But first you should check if the mode is enabled. Perhaps its additional activation will not be needed.

In the simplest case, when starting a computer terminal or laptop, you need to go to the BIOS settings and access the SATA Mode section.

In the operating system itself, you can use the “Device Manager”, called from the “Control Panel”, administration or the “Run” console with the command devmgmt.msc and go to the IDE ATA/ATAPI controllers section. When this mode is enabled, the AHCI controller will be displayed in standard devices. If it is not on the list, you will have to decide how to enable AHCI in the system. Again, the decision depends on which version of Windows is installed on the computer.

How to enable AHCI mode in Windows 7

So, first, let's look at the "seven". For the seventh and tenth versions, the actions look somewhat similar, but for Windows 8 they are quite different.

• The first step is to call the registry editor (regedit in the Run console).
• Expand the HKLM thread.
• Through the SYSTEM, CurrentControlSet directories and the final Services directory, reach the msahci folder.
• On the right, call up the menu for editing the Start parameter and set its value to zero.
• Now in the Services directory you need to find the IastorV directory, in which, for the Start parameter, actions similar to those described above are performed.
• Only after completing these procedures, the question of how to enable AHCI in the BIOS without catastrophic consequences for the system will cease to be a problem.

Actions in Windows 8/8.1

For Windows 8, the above method will not work, since there is a simpler solution. In this case, you first need to set the system to minimum boot mode in safe mode. How to enable AHCI? Simple enough.

• To do this, first call the command line (necessarily as an administrator), and enter the combination bcdedit /set (current) safeboot minimal.
• After this, you need to reboot, at the very beginning of the restart, enter the BOIS settings and then switch the mode from IDE to AHCI.
• After saving the settings, a reboot follows again, the command console is called, and the line bcdedit /deletevalue (current) safeboot is written in it, after which another restart of the computer follows.

In principle, the question of how to enable AHCI in the G8 can be resolved by using a special utility from Intel (of course, if you have a processor from this particular manufacturer).

• First, you need to download the driver in the form of the f6flpy file and the SetupRST.exe customizer from the official resource.
• After this, the desired hard drive is selected in the “Device Manager”, the driver update procedure is applied, and the downloaded f6flpy file is manually specified as the driver itself.
• This is followed by a reboot, and after the system starts with the AHCI mode already activated, the SetupRST executable configuration file is launched to complete the computer setup.

How to enable AHCI on Windows 10?

As already mentioned, for the tenth version of the system the actions are somewhat similar to those performed in Windows 7. The only difference is the selection of folders and parameters.

• In the system registry we find the Services directory. Here, the storahci directory is used for the Start parameter.
• Next, zero values ​​are set for parameter 0 in the storahci/StartOverride and iaStorV/StartOverride directories.
• After this, you can begin to activate the primary value in the BIOS primary input/output system settings.

By the way, in the eighth version of the system, editing similar parameters can also be done. But why, if there is a simpler rational solution to the problem?

Activating AHCI in BIOS

To enter settings on desktop computers, the Del key is most often used, and for laptops - F2, F12, combinations with the Esc and Fn keys, or special buttons on the panel like ASSIST in Sony VAIO.

Here you need to find the AHCI mode section or settings. How to enable the required parameter in the BIOS? Just use the enter key on the SATA mode setting line, and select a parameter using the arrows with confirmation in the form of another press of Enter. When exiting, don’t forget to save the changes (F10 + Y) and reboot the system. When you restart, the system will automatically install the necessary drivers.

Possible problems

Unfortunately, sometimes unexpected errors may occur when switching to AHCI mode. Perhaps the hard drive itself does not support this mode of operation. In this case, there is no point in trying to activate AHCI.

On the other hand, if the system boots, but some errors are displayed or crashes occur precisely after switching from IDE to AHCI, you can try to troubleshoot using a specially developed utility from Microsoft called Fix It.

If neither one nor the other helps, you will have to call up the BIOS settings again and change the operating mode of the hard drive. Please note: if AHCI was activated without performing the preliminary steps in the system registry described above, these methods may not work. The solution is either a system restore using removable media or a complete reinstallation of Windows. So be careful. However, I would like to hope that it will not come to this (of course, provided that the entire sequence was completed exactly in the order that was given in the description).

When repeating or clearing, you can initially enable this mode in the BIOS, so that later you don’t have to rush around looking for a solution to activate it or troubleshoot problems and malfunctions in your computer or laptop.

Instead of a total

In conclusion, it remains to add that inexperienced users who are not familiar with the intricacies of setting up the primary BIOS system and Windows operating systems should not activate this mode unless absolutely necessary. All the same, on modern computers with powerful processors and large amounts of RAM, the performance increase will not be particularly noticeable. On old terminals or laptops there is no point in using this mode at all. Basically, as already mentioned, such settings are more suitable for servers when the hard drive is accessed by several dozen child terminals on the local network.

The AHCI mode of operation of SATA hard drives allows you to use NCQ (Native Command Queing), DIPM (Device Initiated Power Management) technology and other features such as hot-swappable SATA drives. In general terms, enabling AHCI mode allows you to increase the speed of hard drives and SSDs in the system, mainly due to the advantages of NCQ. This instruction describes how to enable AHCI mode in Windows 10 after installing the system, if for some reason reinstallation with AHCI mode previously enabled in the BIOS or UEFI is not possible, and the system was installed in IDE mode. I note that for almost all modern computers with a pre-installed OS, this mode is already enabled, and the change itself is especially important for SSD drives and laptops, since the AHCI mode allows you to increase SSD performance and, at the same time (albeit slightly) reduce power consumption. And one more detail : the described actions in theory can lead to undesirable consequences, such as the inability to start the OS. Therefore, take them on only if you know why you are doing it, know how to get into the BIOS or UEFI, and are ready to correct unforeseen consequences if something happens (for example, by reinstalling Windows 10 from the very beginning in AHCI mode). Find out. Whether AHCI mode is currently enabled can be done by looking at the UEFI or BIOS settings (in the SATA device parameters) or directly in the OS (see screenshot below).
In order to enable the operation of hard drives or SSDs, we will need Windows 10 administrator rights and a registry editor. To launch the registry, press the Win+R keys on your keyboard and enter regedit.

If you have UEFI, in this case I recommend doing this through “Settings” (Win + I) - “Update and Security” - “Recovery” - “Special boot options”. Then go to “Troubleshooting” - “Advanced options” - “UEFI Software Settings”. For systems with BIOS - use the F2 key (usually on laptops) or Delete (on a PC) to enter the BIOS settings (