How should a hard drive work? What is AHCI, IDE, SATA? AHCI or IDE - which is better? Description of the mode, characteristics

At one time, hard drive developers were looking for various ways to improve the performance of the disk subsystem, which remained relatively slow from year to year, and progress in the storage environment consisted mainly of increasing HDD capacity. Gradually, the SATA standard and corresponding versions of this interface appeared, which brought some new technologies.

In fact, there are only two common technologies - “Hot Plug”, that is, hot-swappable drive and “NCQ” (Native Command Queuing), a native (innate) command queue. The first technology is quite simple, it allows you to simply remove drives on the fly without turning off the computer, although for this you still need to use their software shutdown. NCQ was able to add speed to hard drives, and even more so, it will be able to do this with SSDs, which cope well with “deep queues”.

These, as well as some other options, will work if the drive controller is set to SATA AHCI mode. In turn, AHCI (Advanced Host Controller Interface) is an advanced controller operating system that is only available in this (AHCI) operating mode.

The good news is that all modern platforms support the AHCI mode of operation of the internal SATA controller, and it can be easily selected in the settings of the main EFI or BIOS shell.

The bad news is that if the operating system was installed in normal "IDE" controller mode, it will not boot and will freeze after selecting AHCI and attempting to start. That is, you may need to reinstall the operating system. Moreover, to install Windows XP (which, however, is not recommended when using an SSD), you will need to have AHCI drivers in advance, otherwise the OS will simply be impossible to install.

Important: You can enable AHCI support on Windows 7 without reinstalling the OS. To do this, before switching the controller to AHCI mode, you need to go to the registry editor.

Editing a registry setting.

Call the command line (ALT + R) and write “regedit”, of course, without quotes;
Find the registry key “HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci »;
Find the “Start” option and double-click on it. In the "value" field, enter "0". That's it, the system can be restarted and set to AHCI mode.

So does it make sense to use the AHCI mode of the SATA controller? There is definitely a point. Let's take a quick look at the benefits again:

Support for hot-swap drives;
Overall productivity increase from NCQ technology;
Operation at maximum speeds (relevant when using a controller and SSD SATA-600);
Support for additional commands, such as TRIM.

Yes, the TRIM command will only work on the operating system installed on the drive running in AHCI controller mode. You can learn about the importance and usefulness of this command. So there is no reason to use the controller's standard IDE compatibility mode.

Read, how to determine in what mode the computer controller is operating. And, how to activate the AHCI mode of the SATA interface on a computer with Windows already installed. Many people will reasonably ask: why do we need IDE mode for a SATA drive if the AHCI mode is its “native” mode and is the one in which the SATA drive will operate adequately for its characteristics and purpose. Moreover, many motherboard manufacturers set their PATA compatibility mode to IDE by default.

The SATA interface can operate in two modes, IDE and AHCI:

IDE is a compatibility mode for older hardware and software. Essentially, the capabilities of SATA in this mode are no different from those of its predecessor, the ATA (or PATA) interface;
AHCI is a new mode for working with storage devices in which the computer uses all the advantages of SATA, the main ones being: higher speed of hard drives and SSDs (Native Command Queuing or NCQ technology), as well as the ability to hot-swap hard drives. Activating AHCI mode helps speed up access to files stored on storage devices and has a positive effect on the overall performance of the computer.

Many people will reasonably ask: why do we need IDE mode for a SATA drive if the AHCI mode is its “native” mode and is the one in which the SATA drive will operate adequately for its characteristics and purpose. Moreover, many motherboard manufacturers set their PATA compatibility mode to IDE by default.

The thing is that operating systems began to support the controller in AHCI mode starting with Vista. That is, if a disk with Windows XP is connected to a system whose controller operates in AHCI mode, the user will receive a BSOD error (“blue screen of death”). And on the other hand, any SATA drive can freely operate in IDE mode. Moreover, many users, not knowing about it, will not even feel any difference. In this way, computer manufacturers are trying to avoid possible problems with the compatibility of the computer and user software.

Another important difference between IDE and AHCI concerns working with SSD drives. Please note that it is not possible to install an operating system in IDE mode on an SSD; this will require AHCI activation.

How to determine in what mode the computer controller is operating?

It is likely that AHCI mode is already activated on your computer. You can check this in several ways:

Method 1

Go to
Open section “IDE ATA/ATAPI Controllers”
If there is a device in this section with the word “AHCI” in the name, as in our case, then the AHCI mode on the computer is already in use.

Method 2

Please note that in the BIOS of some computers there is no option to change the mode to AHCI. In this case, the problem can sometimes be solved by updating (flashing) the BIOS version.

How to activate the AHCI mode of the SATA interface on a computer with Windows already installed?

There are several ways to activate the AHCI mode of the SATA interface on a computer with Windows already installed, while maintaining its functionality:

FIRST:

If for some reason the first method did not work, also pay attention to second option. But first, if you are having errors when starting Windows in AHCI mode, return to IDE mode and turn on your computer.

After that:

As you can see, the described actions in theory can lead to undesirable consequences, such as the inability to start the operating system. Therefore, take them on only if you know why you are doing it, can access the BIOS or UEFI, and are ready to correct unforeseen consequences if something happens. For example, by reinstalling Windows from the beginning in AHCI mode.

What is AHCI mode and why should it be enabled? AHCI is a mechanism for working with information storage devices. For example, with hard drives or SSD drives. This mode replaces the more outdated IDE mode. The dawn of this “protocol” came, perhaps, in 2011. At that time, prices for SSD drives became more or less affordable for home use.

We will not disclose all the technical details about how the AHCI mode works. It will be enough for an ordinary user to know that with AHCI enabled, the speed of working with the disk and its service life increase. But to experience all the beauty of its work, an SSD drive with a SATA 6Gbit interface must be installed in your computer.

This is where we will finish the story about the details of the operation of the AHCI mode and move on to considering the issue of enabling it in the system.

It’s worth mentioning right away that the connection mode for AHCI drives must be supported by your motherboard. Fortunately today, we can confidently say that almost any motherboard released from 2008 onwards has this capability.

Increase PC speed using AHCI mode

What is the difficulty when switching to AHCI mode? If you are just going to install the operating system, then no problems will arise. You just need to enable this mode in the BIOS of your computer and only then install Windows. Usually enable AHCI it is possible through the BIOS in the section on working with storage devices Storage Configuration.

On different models of motherboards, this section may have a different but similar name. For example, SATA Configuration, SATA Mode, etc. The guideline for your search will be the ability to select from a list of the following modes: IDE, AHCI, RAID.

Switching to AHCI without reinstalling the operating system

So, we figured out installing a clean OS, everything is simple! Now let's look at the situation of turning on AHCI for already working Windows. The fact is that when you change modes in the BIOS, the operating system will stop loading with various types of errors.

These errors are caused by the absence of the required hard disk controller driver when loading the OS. That is why, before changing the BIOS settings, we will need to prepare the operating system.

To do this, open the Registry Editor through the menu Start > Run > Regedit and we will find the following subsections in it:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV

In each section you will need to open the parameter Start and replace its value with - 0 .

After making changes, you need to restart the computer, go into the BIOS, enable AHCI mode and save the changes. When the operating system first starts, it will install the new driver and be ready for further work.

As a rule, this method works and is suitable for all versions of Windows from version 7 and higher. If you were unable to figure it out with the first method, then you can try to enable AHCI mode a little differently or contact our team for help.

In order to get a fast computer, sometimes it is not enough to simply buy a solid-state SSD drive and install the system on it. In some cases, additional fine-tuning of the operating system and computer BIOS is required. One of these tweaks is the inclusion of AHCI mode, which is necessary for the correct operation of some functions.
What is AHCI mode? Advanced Host Controller Interface is a special technology that is used in the Serial ATA protocol through which the PC hard drive is connected. It allows you to use certain advanced functions that are essential for the correct and fast operation of solid-state drives. For example, NCQ (Native Command Queuing), which makes it work much faster.
How to switch the controller to AHCI mode?! The current operating mode of the SATA controller is changed in the parameters of the Basic I/O System. To do this, you need to go into the BIOS or UEFI when you boot your computer. Depending on the system version, the SATA controller configuration parameters in the BIOS may be located in the “Integrated Periferals” section:

Or in the “Main”>>”Storage Configuration” section.

In UEFI BIOS everything is almost the same. You need to find the SATA Controller configuration section either in the main settings:

Or in extended mode - “Advanced Mode”.

Among the three available modes you must choose AHCI mode. All that remains is to save the configuration settings and restart your computer or laptop.

Enabling AHCI on Windows 10

If you want to change the operating mode of the controller on an already installed Windows operating system, then you also need to set a couple of parameters in it. To do this, you need to call the Windows Registry Editor and open the branch:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci
In it you need to double-click on the parameter Start to open its properties for modification:

Set the parameter to “0” and click on the OK button.
Next, open the thread:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iaStorV
There should also be a parameter here Start:

It also needs to be set to “0”.
Close the registry editor and restart your computer or laptop so that the AHCI mode works.

Note: If you are still using the old Windows 7, then enabling AHCI is not done using the “msahci” registry branch instead of “storahci”. Otherwise, everything is exactly the same.

Maximum performance is achieved when using the AHCI mechanism. Therefore, all new PCs that run the Windows 7 operating system or older versions of the OS from Microsoft use this option. If we are talking about older systems, then you still need to think about whether to use AHCI or IDE. What's better? The answer to this question depends on many factors.

AHCI or IDE - which is better? How to choose the desired mode?

Despite the popularity of the Windows 7, 8, 10 operating systems, many owners of personal computers and laptops continue to use Win XP. The OS is stable. People feel comfortable working with her. However, Windows XP also has a number of significant disadvantages:

official Microsoft support for this OS has been completely discontinued;
technologically outdated operating system;
does not support new versions of DirectX (versions 10-12);
safety problems;
there is no support for the most current technologies;
It is impossible to install many modern programs on XP;
There are no drivers for new equipment.

The list could go on for a long time. If we consider the question of which operating mode is better - AHCI or IDE - then it is worth taking into account the fact that Windows XP simply does not support the first option. This, of course, also applies to older versions of the Microsoft OS. Therefore, the choice here is obvious - only IDE. But if a person belongs to the category of advanced users, he can load special drivers into the system that allow the use of the AHCI mechanism. By default, this mode is not supported.

How IDE mode works

Components that require an ATA interface for connection use the IDE mechanism to operate. This technology is outdated, but it was widely used in the nineties of the last century and at the beginning of the 2000s. The standard was introduced in the IBM PC - the first mass popular computers.

The IDE (parallel drive interface) mechanism provided data transfer at a speed of 150 Mbit/s. It did not allow the use of some technological solutions that were relevant at that time. Thus, it was impossible to hot remove a hard drive or CD drive from the system without shutting down or rebooting the system. Similar features were added by engineers some time later, but only a portion of computers received their support. Knowing the background of the development of interfaces, you can easily answer a number of questions: AHCI or IDE - which is better for a specific operating system, which scheme provides faster operation?

Active use of Parallel ATA interfaces ended around 2006, when the new SATA standard began to play a major role. However, even after 10 years, the IDE is still in use, although it is used much less frequently. The mechanism is used in almost all old computers and laptops, and is active even in systems that support AHCI.

Features of AHCI mode

The emergence of the new SATA interface, which had more powerful capabilities compared to the previous PATA technology, created the need for a new mechanism for working with the system. This is how AHCI mode appeared. It allowed the resources of the newly appeared interface to be used to their full potential. Today, this mechanism is supported by all modern motherboards.

Using the AHCI mode allows you to transfer information at the highest possible speed and use any current technological solutions. All current operating systems have device drivers that operate this protocol. So what should you choose now, IDE or AHCI? What is better for a modern computer? In most cases, the choice should be made in favor of the second option.

Advantages of the AHCI mechanism

Modern drives with SATA interface are fully compatible with the new mode. What advantages does this mechanism have? Still, choose IDE or AHCI - which is better? Windows 7 and newer versions of Microsoft OS are capable of working with the two above protocols. But the second one is better used for new systems.

Benefits that the user receives when using AHCI:

high data transfer speed;
excellent performance;
full compatibility with modern operating systems;
the ability to hot-swap hard drives;
support for NCQ technology (improves HDD performance).

Knowing about all the pros and cons of the solution, it’s easy to make a choice between installing AHCI or IDE in the settings. What would be better for a modern computer? If it is not equipped with PATA drives, it is better to install a new mode.

Which mode to set in BIOS settings

Although IDE mode has long been obsolete, it is still supported by motherboard manufacturers. Even the newest models have the ability to use this interface. In the BIOS settings in the corresponding section, you can change one mode to another. By default, the AHCI engine is usually installed. You can run into an exception, but this happens extremely rarely.

If we take a typical situation where a user is trying to install the Windows 7 operating system on a computer, then he does not even have to make any changes to the BIOS to use the new scheme. Perhaps some will find it familiar to work with the old interface. So, IDE or AHCI - which is better? Windows 7 allows you to use both modes.

If your hard drive or other storage device is connected to the motherboard via a SATA interface, you should leave the default AHCI mode. Full support for this mechanism is provided in the operating systems Windows 7, 8, 10, Ubuntu 16.04 and others. Only with the new mode is stable operation of OS data possible.

What to do if, after enabling AHCI mode, the system stops booting

This situation may arise if the user has Windows XP or an older version of Linux installed. There is no question here whether to prefer AHCI or IDE. What will be better for the old OS? Perhaps it is preferable to set the mode to IDE. You can try to install additional drivers on the system that provide support for the new standard. However, there is no guarantee that after this procedure the OS will work correctly.

In some cases, a computer that has successfully worked for a long time running Windows XP one day stops booting. At the same time, the user did not change the operating mode of the drives in the BIOS. This situation may occur due to errors in the underlying I/O system. In this case, the settings are reset and the AHCI mode is activated. The user must independently install support for the IDE mechanism in the BIOS settings.