12pak

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Nov 7, 2011
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Hi. I just got a 1TB Western Digital HD with 6gbs support. My new mobo, GA-990XA-UD3 is supposed to support this 6gbs speed. I only have the one drive. Do you have to do a RAID setup to utilize the 6gbs or will one drive attain this speed? Also, in my BIOS, the drive is set for IDE. I see the option to enable AHCI, but I have no clue what the difference is, (description in the manual is very brief and vague, only tells me that I can enable it). Is there any benefit in enabling the AHCI with only one drive? Please help!!
 

chesteracorgi

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No hard drive will utilize the 6.0 Gb/s bandwidth, only a SSD will come near. RAIDing the drive will not touch it either. The problem is the physical spin speed of the media.

If you plan to get a SSD later then go AHCI: it is necessary for using trim on a SSD. Use IDE only if you need it for a legacy drive.
 
If you have any intentions of ever getting a ssd then you should enable the ahci in the bios because the ssd's will utilize the feature and once you load the operating system you cannot enable ahci unless you do the reistry hack or reload windows. If you are sure you will never get a ssd then leave the ide setting.
 
AHCI also enables features such as hotswap, NcQ(helps a hard drive streamline its operation).

As said about, it is best to enable it before installing windows. With XP you need to install a driver in windows install from a floppy or floppy image on USB drive(slip steam may also be an option). Windows 7 has a native driver to support AHCI.

As said, sata 6 is not gonna help hard drive speeds.
 

12pak

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Nov 7, 2011
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Ok, thanks for the responses. I do have windows 7, but when i installed the default was IDE. So if i dont want to do a reinstall just yet then the recommendation is to leave it as IDE in the Bios? Looks like i got favor of both in responses, so still a little confused. What happens if i switch to AHCI in bios without reinstalling?
 

funguseater

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Hi if you install as IDE you can switch like this:

Switching from IDE to AHCI Disc Mode

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully.

To resolve this issue yourself, enable the AHCI driver in the registry before you change the SATA mode of the boot drive. To do this, follow these steps:
Exit all Windows-based programs.

Click Start, type regedit in the Start Search box, and then press ENTER.
If you receive the User Account Control dialog box, click Continue.
Locate and then click one of the following registry subkeys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
In the right pane, right-click Start in the Name column, and then click Modify.
In the Value data box, type 0, and then click OK.
On the File menu, click Exit to close Registry Editor.


PS. you can also copy this into a notepad file and SAVE AS > ahci.reg then just run the file.

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci]
“Start”=dword:00000000

REMEMBER after you do the reg hack you need to change your BIOS setting to AHCI.

Have fun!
 

Craiga1954

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Mar 28, 2012
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Thanks all,

This helped me solve a problem on an HP MS218 AiO in an Enterprise environment.

The symptom was not booting correctly. Launch repair would not work even with the correct installation DVD.

I reinstalled Wondows 7 Pro from OEM DVD and it worked fine. After installing an image (volume license) it failed again.

Checked SATA controller in BIOS and found it was IDE. Changed to AHCI and viola.

Issue resolved!
 

JamesTKirk3000

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Jan 21, 2016
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4,510
bump an old thread!

WOW! i can't believe it worked! thanks Funguseater!

i've got a SSD and i'm trying to configure BIOS/OS for best performance. that registry hack was perfect. i was getting the blue screen after boot on Win 7.

no more. i changed the value for ...\msahci . perfect!

-Kirk Out