AHCI support is included in Windows operating systems from Vista replacement of old IDE and among the advantages it brings is the Queuing native commands which allows the hard disk controller to optimize read and write access to the unit by modifying the order of the requests addressed to it. In other words, in a storage unit, if a subsequent request points to a sector of the hard drive that is closer to the present than the next, it will move it forward.
Another very important improvement in servers is the ability to hot plug and unplug storage drives. Which means we can change them without having to turn the server off and on again, which in some specific applications can be fatal. Imagine, for example, that you had to change the storage unit into a server that controls traffic and with it the traffic lights of a large city.
How to activate AHCI mode?
When installing Windows, see how we configured the SATA interface, if it sees that we have it in IDE mode, it will not install the internal drivers to communicate with the storage unit in AHCI mode . Although the access mode can be changed from the hard drive, we have to keep in mind that this can lead to general failure of the operating system. The reason is that we have changed the rules with which it must communicate with the hard drive.
However, it is not necessary to reinstall the operating system to activate the AHCI mode, for this it is enough to access the command prompt as administrator.
It is important that you access it with full permissions and once inside type the following on the command line:
bcdedit / set {current} minimal safeboot
This will make Windows start in Safe Mode the next time it reboots, but before that we need to do some preliminary steps. Save all your work, close applications and restart the computer, however, make sure to access BIOS and from storage options enable AHCI mode.
Save changes in BIOS so that they are not lost and you will see that then Windows starts in Safe mode. As you already know, in this mode the operating system loads with the minimum number of drivers to function and the consequence is that it will detect that the AHCI mode is active so it will load them. You’ve already managed to switch from IDE mode to AHCI mode without having to reinstall Windows, however, we’re not done yet with no final little details left.
Go to the command prompt again as administrator and type:
bcdedit / deletevalue {current} safeboot
Like the other time, don’t forget to press Enter key for the command to be executed, with this we always disable boot in safe mode and you will be able to use AHCI mode in Windows 10.
What is IDE mode for on a SATA disk?
Currently not at all, however, if we have to work with a very old operating system such as Windows XP, keep in mind that it does not support AHCI. There are still many people who use daily programs necessary for their work which have not been adopted by later versions of Windows or who use a very old version of GNU / Linux which does not support it. And speaking of the penguin operating system, unlike Windows, it will be set to one mode or another automatically when changing modes from BIOS.
IDE mode therefore exists for backward compatibility and is therefore a holdover from the days when we had hard drives with an IDE interface. Who have been out of the market for a long time. Today it is difficult for us to find a PC that is not configured as standard in AHCI mode today, although you never know and you may end up with a surprise, so it never hurts to take a look at the BIOS.
Does this make sense for SSDs? SATA
Well, you could say that in theory the advantages of AHCI are less for an SSD, because the latency of accessing a part of it does not depend on the position it is in. An SSD is not a disk drive and is not divided into sectors of different access speeds, so optimizing access based on the position of the sectors on the disk with Native Command Queuing results in nothing, rather a loss time for the Flash SSD controller, but no
However, it has some advantages in SSD and the causes are curious to say the least, because in a solid state drive it is not the same to access the following memory address, remember that they work like ram which is another hit and miss. In other words, the AHCI mode can exceed the sequential accesses before the others.
Anyway, with the SATA interface with the sword of Damocles on top and with the existence of NVMe SSDs, AHCI mode becomes a thing only for hard drives.
