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jobin481g
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Dell G5 5590 Not booting in AHCI mode

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I recently bought a dell g5 5590. its configuration details says it is came with an NVME boot ssd. I upgraded the HDD to 2TB hdd. its working on UEFI booting mode. But my system is not booting when im turning on AHCI mode in bios. Why its happening so?

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jphughan
5 Tungsten

Re: Dell G5 5590 Not booting in AHCI mode

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@jobin481g  ok first of all, AHCI and UEFI are not "opposites".  They're completely different things that are configured in completely different sections of the BIOS Setup.  UEFI is a boot type, and the other boot type option is Legacy (aka BIOS).  AHCI is a storage interface operation mode, and the other option there is RAID.  Despite the "SATA Operation" setting name, it also affects how the system treats NVMe SSDs.  But the point is that you can can have a system that boots in UEFI mode and runs its storage interface in AHCI mode -- or a system that boots in UEFI mode and runs its storage interface in RAID mode, which is the factory default configuration.

The reason you're having an issue is that as you should have been warned when you tried to change the RAID setting to AHCI, that setting isn't meant to be changed on an installed OS.  It's designed to be changed before you reinstall an OS.  The reason is that if Windows is installed while the system is in RAID mode, then it will configure itself to load the Intel Rapid Storage driver at boot in order to see the storage device.  If you then reconfigure the system to run in AHCI mode, then Windows won't be configured to load the correct driver at boot anymore, so it will fail.  In order to reduce boot time, there are certain devices and drivers where Windows does NOT dynamically adjust based on the installed hardware and its configuration.  Instead, it just stores assumptions about how the hardware will be configured, so if you change the hardware configuration, then those assumptions are invalid and Windows doesn't start.  The same would occur if you had installed Windows while in AHCI mode and later decided to switch to RAID.

There are some manual hoops you can jump through in order to switch an existing Windows installation over to AHCI mode.  They involve booting in Safe Mode at some point and possibly some other tasks.  I haven't looked into them in detail.  But if you were to perform multiple benchmarks in both RAID mode and AHCI mode, I doubt you'd see much of a consistent performance difference, if any at all.  So if you're not all that techy, you might want to just leave this one alone.

7 Replies
U2CAMEB4ME
3 Zinc

Re: Dell G5 5590 Not booting in AHCI mode

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Welcome to the Dell Community  @jobin481g 

Why are you trying to boot in "AHCI" mode???

If the OS was configured and built with "UEFI" you cannot simply switch it to "AHCI" and boot.

There are processes to switch from "UEFI" to "AHCI" boot mode.

Or you could switch to "AHCI" and install a fresh OS.

Best regards,

U2


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Saltgrass
4 Germanium

Re: Dell G5 5590 Not booting in AHCI mode

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Many Dell Systems, so I assume yours, come with NVMe drives being controlled by the Intel SATA/PCIe controller.  For the M.2 slot to function in that manner, the SATA controller in the Bios needs to be set to RAID.

You can change the controller using a special procedure but the performance with the newer Intel SATA/PCIe Premium controller is almost as good as using the NVMe controller.

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XPS 2720, Inspiron 17 7779, Inspiron 15 7567, XPS 13 9365, Inspiron 1545, TB16 Dock

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jobin481g
1 Nickel

Re: Dell G5 5590 Not booting in AHCI mode

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Im not an expert tech guy. i head ssd drives would be faster if it is in ahci mode so i just asked my doubt here

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U2CAMEB4ME
3 Zinc

Re: Dell G5 5590 Not booting in AHCI mode

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@jobin481g 

Just leave it in "UEFI" mode.

Then set the new 2TB drive as default storage and you should be good to go.

Regards,

U2


Microsoft Registered Refurbisher
Microsoft Registered Partner
Windows Operating System lifecycle fact sheet
Lifecycle begins when released and ends when no longer supported
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jphughan
5 Tungsten

Re: Dell G5 5590 Not booting in AHCI mode

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@jobin481g  ok first of all, AHCI and UEFI are not "opposites".  They're completely different things that are configured in completely different sections of the BIOS Setup.  UEFI is a boot type, and the other boot type option is Legacy (aka BIOS).  AHCI is a storage interface operation mode, and the other option there is RAID.  Despite the "SATA Operation" setting name, it also affects how the system treats NVMe SSDs.  But the point is that you can can have a system that boots in UEFI mode and runs its storage interface in AHCI mode -- or a system that boots in UEFI mode and runs its storage interface in RAID mode, which is the factory default configuration.

The reason you're having an issue is that as you should have been warned when you tried to change the RAID setting to AHCI, that setting isn't meant to be changed on an installed OS.  It's designed to be changed before you reinstall an OS.  The reason is that if Windows is installed while the system is in RAID mode, then it will configure itself to load the Intel Rapid Storage driver at boot in order to see the storage device.  If you then reconfigure the system to run in AHCI mode, then Windows won't be configured to load the correct driver at boot anymore, so it will fail.  In order to reduce boot time, there are certain devices and drivers where Windows does NOT dynamically adjust based on the installed hardware and its configuration.  Instead, it just stores assumptions about how the hardware will be configured, so if you change the hardware configuration, then those assumptions are invalid and Windows doesn't start.  The same would occur if you had installed Windows while in AHCI mode and later decided to switch to RAID.

There are some manual hoops you can jump through in order to switch an existing Windows installation over to AHCI mode.  They involve booting in Safe Mode at some point and possibly some other tasks.  I haven't looked into them in detail.  But if you were to perform multiple benchmarks in both RAID mode and AHCI mode, I doubt you'd see much of a consistent performance difference, if any at all.  So if you're not all that techy, you might want to just leave this one alone.

jobin481g
1 Nickel

Re: Dell G5 5590 Not booting in AHCI mode

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Ok, thank you buddy

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U2CAMEB4ME
3 Zinc

Re: Dell G5 5590 Not booting in AHCI mode

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Your very welcome @jobin481g 

Regards,

U2


Microsoft Registered Refurbisher
Microsoft Registered Partner
Windows Operating System lifecycle fact sheet
Lifecycle begins when released and ends when no longer supported
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