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Could someone quite simply just explain the different HDD modes to me...IDE...ACHI etc

As I've just flashed my MOBO and Windows wouldn't work until I changed HDD to ACHI in BIOS...I have no idea what these different types mean - Just a general overview would be great!
6 answers Last reply Best Answer
More about simply explain hdd modes ide achi
  1. They are a set of commands for controlling the HDD basically.

    IDE: Legacy from older IDE/PATA drives supports less commands etc

    ACHI: Newer set for SATA drives. Finer control of the drive and more supported commands
  2. SATA ports can have 3 settings (modes): IDE, AHCI, & RAID.

    Optical drives (CD, DVD, Blu-ray, etc.) normally use IDE mode.

    Older HDDs normally use IDE mode. Current generation HDDs have slightly better performance in AHCI mode.

    SSDs need to be in AHCI mode. They will work in IDE mode, but at reduced performance.

    If you are combining multiple HDDs or multiple SSDs into a RAID array then the drives being used in the array have to be in RAID mode.
  3. Dereck47 said:
    SATA ports can have 3 settings (modes): IDE, AHCI, & RAID.

    Optical drives (CD, DVD, Blu-ray, etc.) normally use IDE mode.

    Older HDDs normally use IDE mode. Current generation HDDs have slightly better performance in AHCI mode.

    SSDs need to be in AHCI mode. They will work in IDE mode, but at reduced performance.

    If you are combining multiple HDDs or multiple SSDs into a RAID array then the drives being used in the array have to be in RAID mode.


    What's a RAID array? Thank's all for the answers so far :))

    I am thinking of changing to SSD for main drive, and HDD for storage, would they need to be in RAID...or ACHI?
  4. evansuk2000 said:
    Dereck47 said:
    SATA ports can have 3 settings (modes): IDE, AHCI, & RAID.

    Optical drives (CD, DVD, Blu-ray, etc.) normally use IDE mode.

    Older HDDs normally use IDE mode. Current generation HDDs have slightly better performance in AHCI mode.

    SSDs need to be in AHCI mode. They will work in IDE mode, but at reduced performance.

    If you are combining multiple HDDs or multiple SSDs into a RAID array then the drives being used in the array have to be in RAID mode.


    What's a RAID array? Thank's all for the answers so far :))

    I am thinking of changing to SSD for main drive, and HDD for storage, would they need to be in RAID...or ACHI?



    Raid is a system to combine multiple HDD together in certain combinations for performance, redundancy, or both.

    For that leave it in AHCI. RAID is only when you have a RAID array.

    Explaining RAID is easier if you read up on it
    http://en.wikipedia.org/wiki/RAID this makes a fairly decent explaination.
  5. Best answer
    Yes, if you're going to have a SSD as your O/S dive and a HDD for storage, have them both in AHCI mode for best performance.
    Your motherboard manual will show you how to change SATA modes.
  6. Thanks everyone for the answers! Was hard to choose.
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