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Windows 7: Registry values for msachi and iaStorV "Start" variable

29 Jan 2012   #1

Windows 7 Ultimate x64
 
 
Registry values for msachi and iaStorV "Start" variable

Right now my values for both

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
and
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\iaStorV

Start variables are set to "3"

My system configuration consists of:

Main HDD (Windows): Single SSD on SATA_0
Secondary HDD: 2 disks in RAID 0 on SATA_1 and SATA_2

Since I'm using onboard RAID 0 for my secondary drive, the BIOS is set to RAID mode.

I've read that for AHCI "Start" in msachi should be 0, but I havent found definitive instructions for RAID mode in BIOS. I am not getting AHCI type functions (safely remove option, etc) with these drives currently.

Can anyone with a similar setup explain what these values mean and what they should be set at? Motherboard is a Gigabyte 970A-UD3 and I am running Windows 7 64-bit.


My System SpecsSystem Spec
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02 Feb 2012   #2

Windows 7 Ultimate x64
 
 

I had thought that RAID was a superset of AHCI, but with my BIOS set to RAID mode I don't get the options I was used to with previous systems using AHCI such as the option to safely remove my SATA drives and policy options for Quick Removal.
My System SpecsSystem Spec
02 Feb 2012   #3

Microsoft Community Contributor Award Recipient

Windows 7 Ultimate SP1 X64 (Windows 8.1, Linux Mint, Windows XP and others in VM)
 
 

Here is a tutorial to change to AHCI mode
My System SpecsSystem Spec
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02 Feb 2012   #4

Windows 7 Ultimate x64
 
 

Thanks, what I'm wondering about is since my BIOS is set to RAID rather than AHCI mode, which of the two values (iaStorV or msachi) should be changed to "0"
My System SpecsSystem Spec
02 Feb 2012   #5

Windows 8.1 Pro (x64)
 
 

If your two drives are in RAID 0 you do not want the ability to hot swap them.
My System SpecsSystem Spec
02 Feb 2012   #6

Windows 7 Ultimate x64
 
 

I have more drives in the system than just the 2 in RAID 0, including an eSATA enclosure that connects to another of the motherboard's SATA ports via a rear bracket adapter.
My System SpecsSystem Spec
02 Feb 2012   #7

Microsoft Community Contributor Award Recipient

Windows 7 Ultimate SP1 X64 (Windows 8.1, Linux Mint, Windows XP and others in VM)
 
 

I have alsways changed both values to 0, no matter which I was really using. Go to device manager and expand IDE ATA/ATAPI controllers and see what driver(s) are listed at the bottom. IaStor is Intel's AHCI driver, but it comes from their IRST package (Raid package).
My System SpecsSystem Spec
02 Feb 2012   #8

Windows 7 Ultimate x64
 
 

There is no IDE ATA/ATAPI controllers section in the Device Manager of this particular system like there usually is in my other builds. I just have "AMD ACHI Compatible RAID Controller" listed under Strorage controllers instead.
My System SpecsSystem Spec
02 Feb 2012   #9

Microsoft Community Contributor Award Recipient

Windows 7 Ultimate SP1 X64 (Windows 8.1, Linux Mint, Windows XP and others in VM)
 
 

OK, that makes sense. If you change that, I'm sure it will break your raid. I have never run raid, but I believe if you change your storage configuration in bios from raid to AHCI, it will break your raid. But, I would also think your non raid drives are in AHCI mode. If you would like to see, download As SSD Benchmark, open it and select your SSD. You don't have to run the test, just post a screenshot of the As SSD window with your SSD selected.
My System SpecsSystem Spec
02 Feb 2012   #10

Windows 7 Ultimate x64
 
 

Oh I definitely can't change my BIOS from RAID. I'm only looking to change Windows registry values so I can have the option to safely remove my eSATA drives. As I said I thought AHCI was a subset of RAID. I think I'm just going to set the msachi value and see what happens.
My System SpecsSystem Spec
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 Registry values for msachi and iaStorV "Start" variable




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