AHCI or IDE - which is better? Description of the mode, characteristics

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AHCI or IDE - which is better? Description of the mode, characteristics
AHCI or IDE - which is better? Description of the mode, characteristics

It is only natural that owners of desktop computing systems and laptops seek to improve their performance in one way or another. To solve this problem, some use the so-called overclocking (overclocking) of components, while others use settings through the capabilities provided by the developers. When choosing any method, it is important to understand what exactly is required to receive, and to be well versed in the features of the chosen method.


It is known that one of the slowest components of a modern computing system is a hard drive based on a classic spindle system. Today, SSD analogs have appeared, but they have not yet received mass distribution due to their high cost.

AHCI or IDE which is better
AHCI or IDE which is better

Therefore, ordinary HDDs are installed on almost every computer. As a result, it turns out that DDR3 memory easily transfers 20,000 Mb / s; the internal bus of the central processor allows to process ten times more data; and a hard drive with the SATA-3 standard only under ideal conditions "accelerates" to real 100 megabytes per second. Notit is accidentally recommended to use productive SSD models at least for system files. From all of the above, a simple conclusion follows: it is the HDD that slows down the modern system, thus being the “bottleneck”. And since the user can easily make changes to the way the disk subsystem commands are processed, affecting the speed to a certain extent, one can often hear the question of which mode is better: AHCI or IDE.


The disk interacts with other components of the computing system through a special control controller. This chip serves as a kind of command translator, a converter. Until recently, the only "language" understood by the controller was the IDE protocol.

what is better ahci or ide
what is better ahci or ide

It originated at the dawn of the computer industry and has been modernized several times. With the advent of high-speed SATA drives, a radical redesign of the protocol was required. This is how AHCI was born. The Advanced Host Controller Interface easily handles the increased data flow (interface), supports the fashionable NCQ command queue, and implements the ability to turn off the device on the go. So what is AHCI? An IDE that adds some new features. It's so simple, at first glance.

Opportunities and prospects

Since the standards are backwards compatible (the SATA device works fine via the IDE protocol), there is almost always an item in the BIOS or its equivalent that allows you to select the desired mode.

ide or ahci which is better windows 7
ide or ahci which is better windows 7

In many cases, only thanks to this, it is possible to achieve normal operation of the computer. The mode selection function is present only in the software of those motherboards that provide for work with SATA. These are all modern systems. However, hybrid solutions can also be attributed here, allowing you to connect both classic IDE devices (PATA, wide connector comb) and SATA (compact connector). So, AHCI or IDE? What's better? To make it easier to understand this, here is a list of "bonuses" that the user receives by activating a more modern mode:

1. The data transfer rate through the internal electronic circuits "disk controller - board controller" reaches from 1.5 Gb / s (gigabit) for SATA-1 modification to 6 in the third revision. Recall that UDMA-6, in which old hard drives can work, provides only 133 Mbps.

which mode is better ahci or ide
which mode is better ahci or ide

2. Speaking about which is better - AHCI or IDE, one cannot but indicate the support for NCQ technology. Its essence lies in the fact that the hard drive can "interfere" in the command stream queue, rearranging them to increase work efficiency.

3. Hot-swappable device without shutting down the entire system.

4. Parallel access to all disks at once, without using sequential switching.

This is such a very tempting list of possibilities. Not surprisingly, the question: "AHCI or IDE: which is better?" is perhaps one of the most painful. Many computer owners, surprisingly, stillbelieve in the “magic button.”

Theory and practice

So after all, AHCI or IDE - which is better? From the above list, we can conclude that the outdated protocol is significantly inferior to the new one. However, this is not quite true. Let's consider this point in more detail. Yes, indeed, the data transfer rate has increased tenfold, however, magnetic disks in hard drives both rotate at a speed of 7200 revolutions (the most popular solution) and rotate. Accordingly, no revolutionary breakthroughs occurred in the reading process. In no HDD test will the user see a 6 Gb transfer. Even 200 Mbps is unattainable! The exception is solid state drives. If such a device is present in the system, then you can not deal with the question: "AHCI or IDE: which is better?", but immediately activate the updated protocol. However, as we pointed out, due to the cost, such drives have not yet become widespread.

Very often in the debate about which is better - AHCI or IDE, the ability of the protocol to support NCQ is cited as the main argument in favor of the first. Indeed, when several programs are actively accessing the hard disk at once, this function allows you to rebuild the request flow in the most optimal way. However, in an average computer, more than two or three programs rarely access the disk at the same time, so it is impossible to speak of a complete lack of acceleration, but it is obtained within the margin of error.

windows 7 switching sata from ide mode to ahci
windows 7 switching sata from ide mode to ahci

IDE or AHCI - which is better? Windows 7 on activationThe latter mode supports connecting/disconnecting a SATA device on the go. Pretty handy, especially on server systems where shutdown is undesirable. Nevertheless, to use "hot swap" it is recommended to use not internal connectors, but SATA modifications brought to the case.

Finally, the protocol allows multiple hard drives on the bus to work simultaneously instead of waiting for requests. It is in this case that the potential of NCQ is fully revealed. Not relevant for the average computer.

As a result, it turns out that although the AHCI protocol, from the point of view of technology, is more interesting, nevertheless, the majority of users will receive nothing but moral satisfaction from its inclusion. There are only two exceptions to the general rule: the server system and the use of SSD.

Usage nuances

Although you can switch modes in BIOS in a few seconds, one important point should be taken into account. It consists in the following: if the operating system was installed, for example, with AHCI, then after transferring to IDE, loading may not be possible. This is not a rule, but most often it happens that way. Therefore, even before installing the distribution kit, you need to decide which disk subsystem protocol you plan to work with.

what is ahci ide
what is ahci ide

AHCI driver packages have only been integrated into the system since Vista. All previous solutions from Microsoft do not have built-in support, so you need to either use "assemblies" or prepare media with the appropriate driver before installation. With a new standardWindows 7 works fine. Switching SATA from IDE mode to AHCI must be done from BIOS (Configure SATA item). In very rare cases, you may need to make changes to the registry.

Switching method

In order to get into the BIOS, immediately after turning on the computer system, you need to press the Delete button (personal computers) or F2 (laptops) several times in a row. Depending on the implementation, the desired item can be in any sections. For example, to activate it, you may need to transfer Boot Mode to CSM instead of UEFI, after which Compatible (IDE) and AHCI appear in the SATA Controller. The item you are looking for may be in the SATA Enhanced section. You need to carefully review the entire existing list. After switching, press ESC and agree to save the changes.


The decision on which protocol to prefer depends on several factors. First of all, from the operating system used. From compatibility at the "iron" level. And of course, from the load on the subsystem. The higher it is, the more preferable AHCI. If we analyze all the reviews, then we can say that both protocols work fine, with the right settings without causing any failures. However, it is more advisable to use the updated version. This, so to speak, was grounded "for the future", for example, for the purchase of an SSD.

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