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bbear2
Premium
join:2003-10-06
94045
kudos:5

How to configure AHCI mode?

MB is currently configured for IDE mode. It also has the options of AHCI and RAID. I'm running Win7 on and HDD but will more to an SSD. Should I change the MB config before installing the OS on the SSD? And if so, should I change it to: AHCI or RAID? What's the difference?

In addition, I've see a registry mod so that Win7 will load the AHCI drivers. Does this same mod (HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci) apply if I choose RAID on the MB vs. AHCI?



aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1

Assuming Win7 or later, you definitely want AHCI, and you definitely want to do that before OS install. RAID mode normally enables AHCI, too, so it's really RAID/AHCI.
--
Wacky Races 2012!


bbear2
Premium
join:2003-10-06
94045
kudos:5

So if I never intend to do RAID, then the plain AHCI is just as good?


n_w95482
Premium
join:2005-08-03
Ukiah, CA

That's correct. While it is definitely best to enable it before installing Windows, it can be done after the fact. I've migrated two PCs in the last couple of weeks from IDE to AHCI in slightly different ways with success (both without involving the registry).
--
KI6RIT


bbear2
Premium
join:2003-10-06
94045
kudos:5

Sounds interesting. Can you share the ways you did the migration?



aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
reply to bbear2

It will be just as good.

Note, it will depend on your BIOS what you need to enable, since, for example, one of my PC has these options:

RAID Autodetect / AHCI
RAID Autodetect / ATA
RAID On
Legacy

In this case, one shall use the 1st option to get AHCI.
--
Wacky Races 2012!


n_w95482
Premium
join:2005-08-03
Ukiah, CA
reply to bbear2

The first PC was a Core 2 system running XP. I forced the SATA controllers to update to these drivers, rebooted, and set the BIOS to AHCI. After that, it booted into XP without any trouble.

The second one was an Ivy Bridge/Win7 laptop I did yesterday. I used a Microsoft FixIt tool, but it looks like that KB page lists the registry key that you mentioned earlier. After doing that, I installed the latest INF update from Intel, but that's optional (it runs fine with the default MS AHCI driver).
--
KI6RIT



berserken

join:2011-03-27
Oakland, CA
kudos:1
Reviews:
·Comcast
reply to bbear2

Along these lines, I made a partition copy of my XP Pro installation to a Vertex2 SSD with gparted. At first, I had to boot in IDE mode, update the driver to Intel's AHCI driver, change to AHCI in BIOS, badda-boom, bada-bing, works fine.

Here's a howto I followed: »expertester.wordpress.com/2008/0···dows-xp/



koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23

1 recommendation

reply to bbear2

Short answer, because I think the replies have gone a bit wild (no offence intended to anyone, don't mean it like that):

As aurgathor See Profile has said, you definitely want AHCI.

Since you're using Windows 7 and now have an SSD, change the BIOS to AHCI mode, then install Windows 7 fresh on the SSD (you already said you were doing that anyway). Don't bother with "migrating" -- just start fresh, as it greatly simplifies the entire process (i.e. way, way less headaches for you). You do not need to touch anything in the registry pertaining to drivers or other silliness -- it all "just works" with Windows 7.

I've already explained the differences between IDE mode and AHCI mode and RAID mode in the past. You can read that. You do not want RAID mode (you aren't using RAID, and it greatly complicates a Windows installation as you now have to give it drivers for RAID support).
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.