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Change IDE to ACHI (easily!) without reinstalling Windows

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Mysterios

Registered
Joined
Jan 11, 2012
Just had to use this process to fully utilise my Vertex 3 240GB SSD. Before I did this it was in IDE mode and running around 300 mbps (slow). I'm now getting about 490mbps :)

I'm putting it on here to help others and to remind me if i need it again in future!

Steps

Go into the registry using regedit and change each of the "start" values in the registry keys below from 3 to 0 and this will allow you to change between the different modes by just changing the option in your bios each time you reboot.


HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\servic es\pciide

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\servic es\msahci

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\servic es\iaStorV

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\servic es\iaStor


You might not have the last registry key (iastor) as this is installed in the registry with the intel raid drivers, the default windows 7 raid driver uses the iastorV key.

And there you have it. Reboot, change the HDD Mode in the BIOS to AHCI and Bob's your uncle.

Cheers.
 
Last edited by a moderator:
In order to enable the AHCI driver in Win7, you should only need to change one of the following registry subkeys (the Start DWORD value; Value data = 0):
Code:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
 
+1 ^^. Been brought up here quite a bit in the past. ;)

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.

http://www.sevenforums.com/hardware-devices/17876-enable-ahci-windows-7-a.html
 
Ok, I changed the values to 0, and ensured BIOS had AHCI was selected.

AS SSD still displaying Corsair as pciide, whilst my WD 1GB HDDs are displayed as msahci.

I double checked BIOS and regedit. Yes, i didnt have AHCI seleceted when i installed Windows 7. Bad me.

Is there another way, such as using Acronis and copying the SSD to a HDD and reinitialising the SSD?
 
Never mind, I misread a label on MB and left one controller (of course the one with the SSD) on IDE.

Thanks, it worked a treat... in the end
 
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