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AHCI?

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December 15, 2010 9:35:12 PM

I understand that if I wanted to get a SSD (such as the Vertex 2), I would need to enable AHCI in the BIOS.

However, I have pullout chasses in my PC which allow me to swap in and out about 7 different hard drives that I use for various data storage. I also have one hard drive which is an XP boot and another which is a Windows 7 boot. I am currently using plain old SATA in the BIOS.

Can anyone please explain what effect turning on AHCI would have to my system? Would I still be able to access the data disks? Would I still be able to boot off the bootable disks?

Thanks!

More about : ahci

a b G Storage
December 16, 2010 12:34:48 AM

Actually, I think AHCI allows hotswap, swaping drives on a running system. It also allows more advanced stuff like NCQ too. Is there any adverse effect, I wouldn't know.

If you need to enable AHCI after installing Windows 7 and don't want to reinstall OS, read this.
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a c 415 G Storage
December 16, 2010 4:18:52 AM

AHCI won't have any impact on your ability to access your disks. The only issue is that you need to get the right drivers installed so that the OS can connect to the disks - follow the link that Zenthar provided to do that.

The reason you need AHCI is because it's required for the TRIM command which helps to optimize SSD performance.
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a b G Storage
December 16, 2010 12:26:27 PM

The ability to detect the RPM of a drive is part of AHCI or IDE? I ask because that is how Windows 7 detects SSD (they report a RPM of "0"), enables TRIM and disables defrag. The later is very important as if defrag stays ON, it might shorten your drive's life (you can always disable it manually).
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a c 415 G Storage
December 16, 2010 3:42:42 PM

Zenthar said:
The ability to detect the RPM of a drive is part of AHCI or IDE?
I don't think RPM detection is dependent on AHCI, I think it's part of the drive ID data that's reported by the drive, and that's been available for a long time. The issue with TRIM is that it's a new storage command that wasn't around when IDE-mode drives and drives were written, so it's not supported by all IDE-mode drivers.

For example, see: http://communities.intel.com/message/97615
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a c 353 G Storage
December 17, 2010 2:13:48 PM

Do not see MB (southbridge chipset).

If INTEL and listed in supported chipsets, the Trim will be passed if the BIOS is set to RAID as long as (1) the disk (SSD) is NOT a member af a Raid set and (2) the Latest Intel RST drivers are used (Ver 9.6). Not sure but when raid is selected and disk is not a member of an Raid array, AHCI is used - Again not positive, stuck in the back of my feeble mind that I read this somewheres.

Also OP stated Bios set to Sata (not Raid, not AHCI). Not sure if he switches bios to AHCI and installs operating system to SSD (WITH other HDDs disconnected), How this affects the read/writes for disks that were orginally configured under sata (after reconnection)

Added - SSDs w/SF1200 controllers prefer the Intel ahci driver (ver 9.6) vs the default microsoft ahci driver loaded by win 7.
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