GUIDE - Enabling AHCI mode AFTER Windows 7 Installation

Discussion in 'SSD and HDD storage' started by Hilbert Hagedoorn, Jan 19, 2010.

  1. Hilbert Hagedoorn

    Hilbert Hagedoorn Don Vito Corleone Staff Member

    Likes Received:
    A little guide:

    I am receiving a lot of emails from users who bought a SSD drive, installed Windows 7 in IDE mode and then realize they need AHCI mode for faster SSD performance. Once you enable that in the BIOS during Windows 7 boot up, the OS will crash.

    The common question is, is there a solve for this ?

    To answer that question (and I do this safely with all Intel ICHR9/10 chipsets) there is a way to safely enable AHCI mode. Here we go:

    1. Startup "Regedit
    2. Open HKEY_LOCAL_MACHINE / SYSTEM / CurrentControlset / Services
    3. Open msahci
    4. In the right field left click on "start" and go to Modify
    5. In the value Data field enter "0" and click "ok"
    6. exit "Regedit"
    7. Reboot Rig and enter BIOS (hold "Delete" key while Booting

    In your BIOS select "Integrated Peripherals" and OnChip PATA/SATA Devices. Now change SATA Mode to AHCI from IDE.

    You now boot into windows 7, the OS will recognize AHCI and install the devices. Now the system needs one more reboot and voilla .. enjoy the improved SSD performance.

    We have not tested this on Vista though.

    Update -- we tested and this tweak works in Vista 100% the same.
  2. DSK

    DSK Guest

    Ok so would there be any advantage doing this with normal HDDs?
  3. Mr.Bigtime

    Mr.Bigtime Ancient Guru

    Likes Received:
    4090 on Laptop
    yeah seeking for same answer..
  4. WhiteLightning

    WhiteLightning Don Illuminati Staff Member

    Likes Received:
    Inno3d RTX4070
    Thanks for the share hilbert :thumbup:

    hilbert do you know if this would cause a blue screen on windows boot, when i only changed it in the bios, and not the registry ?

  5. DSK

    DSK Guest gonna try this i think.
  6. Any chance of some before and after benches Kylzer, before you do this?
  7. DSK

    DSK Guest

    yeah sure..
  8. Hilbert Hagedoorn

    Hilbert Hagedoorn Don Vito Corleone Staff Member

    Likes Received:

    That is correct - if you only change (enable) AHCI in BIOS while the OS was installed with regular SATA then you'll end up with a BSOD during OS bootup.

    The method above describes how to divert that.

    For normal HDDs do not expect any real perf difference.

    AHCI (advanced Host Controller Interface) allows hot-swapping, improves performance allows functions like NCQ, TRIM and so on. It's more flexible and is definitely a notch faster with SSDs seeking high perf in terms of peak performance.

    See below, image 1 has SATA install (left img) - Image 2 AHCI (right img).
  9. DSK

    DSK Guest

    I don't recommend on normal drivers lol


  10. GenClaymore

    GenClaymore Ancient Guru

    Likes Received:
    4070 super
    For me it was the other way around kylzer when I install win7 in achi from IDE on my 500Gb seagate barracuda. I notice the different.

  11. Knox

    Knox Guest

    I've used ACHI mode with a Toshiba and some Seagates, i usually get a small boost (about 5-8 MB/s) or it stays the same. I've never had it hurt any. But i don't usually see WD drives.
  12. deltatux

    deltatux Guest

    I notice a speed increase with AHCI on all my drives. On real world transfer speeds instead of benchmark tests.

    Plus, having NCQ makes it even better.

  13. mR Yellow

    mR Yellow Guest

    So who else tested this in regular HDDs?
  14. TheHunter

    TheHunter Guest

    i tried it once, but i keep seeing this AHCI installing driver in dos every time i restarted pc, i had to wait extra 20sec longer..

    can i use it if i have dual boot? I have win xp and win7, dont want to mess up WinXP..
  15. deltatux

    deltatux Guest

    It's not actually DOS, it's part of your BIOS. I guess GIGABYTE's BIOS doesn't include a native implementation of AHCI so it loads either AMD, Intel or NVIDIA's implementation of AHCI during bootup. It actually allows a bit more functionality if you play with it. It's not DOS and you can use it to install any OS like you do normally.

    I know ASUS doesn't have this issue as I have both ASUS and GIGABYTE boards in my house.


  16. Norvekh

    Norvekh Guest

    Performance depends on your drive controller and drives. In my case enabling AHCI introduces awful stuttering with all of my drives and essentially makes the machine unusable. Disabling it ends the stuttering and gives me higher read/write rates and lower access times.
  17. Acid81

    Acid81 Guest

    Is there any way to do this for XP ?
  18. Darkiee

    Darkiee Master Guru

    Likes Received:
    Thank you Hilbert, a ton.

    My AS SSD bench score went from 204 up to 303 ^^
  19. Year

    Year Guest

    i've always ran my drives in IDE Mode :D

    tried the AHCI trick, it worked but i'm not seeing any performance increase, i do not raid so i don't need it.

    good trick nonetheless that might come in handy someday, worked fine in W7.
  20. dirthurts

    dirthurts Guest

    New to SSD's

    So I read this post and became more confused than I already was. I am adding an SSD to my computer. Fresh install of Win 7.

    Do I somehow set my motherboard to AHCI mode, then Windows 7 will automatically install in this mode?

    Where do I find the AHCI mode in my bios? Foxconn A79A-S

    Any help would be much appreciated.

Share This Page