Alienware 17-R3, RAID/AHCI

The default SATA Operation mode for any kind of disk configuration is called "RAID", but that doesn't automatically mean that your disks are actually in RAID status, as it might lead one to believe - it only means that the storage is controlled by the "Intel Rapid Storage Technology" (IRST).

You can check the status of your two disks by clicking "Intel Rapid Storage Technology" at the bottom of the "Advanced" section, which will take you to a screen where they are listed as "NON-RAID Physical Disks". Here, you can select one of them to see more details like Port, Model and Serial Number, Size, Status (RAID or NON-RAID), Controller Type (AHCI or NVMe) and Controller Interface (SATA or PCIe).

Since the IRST includes both AHCI and NVMe drivers, you won't need to change to or install special drivers for any disks regardless of your hardware configuration now or in future as long as you keep the default "RAID" setting.

I would certainly recommend using "RAID" for a variety of reasons, including that it allows you to use any disk configuration compatible with your hardware without having to install additional drivers when changing or upgrading it. Furthermore I never had any problem with booting or stability as long as the Intel RST managed the storage alone, and. with the included NVMe support my Samsung PM951 performs pretty well (Seq.Read/Write ~1.8K/0.6K). However, as far as I know, you can't switch from "AHCI" to "RAID" without reinstalling Windows.

Contrary to popular belief, you can use the "RAID" mode and still have your NVMe disk be detected during Windows setup, allowing it to be chosen as the system or boot drive. To accomplish this you will just need to use the "Load driver" option that is offered during the setup for a clean installation.

To make the NVMe disk visible just follow the instructions below:

Preparation:

• Download the IRST driver from the Dell Support page.
• Execute it and choose "Extract" instead of "Install" since you will need the unzipped version
• Save all the data on a separate USB stick, giving the folder a name that you will remember.
• Within it, locate the folder "x64" (the location isn`t always the same) - the setup window is very small on a 4k display, you may have trouble finding it later if you dont remember where it is now.
• Using a magnifying glass may also help.

Execution:

• During Windows setup, choose "custom type"
• When you are asked where to install Windows, choose "Load driver".
• Plug in the USB stick and navigate to the x64 folder that you located earlier.
• Select the folder (not the files in it) and confirm.
• Later, when you are asked to choose which driver should be installed, make sure that  "...\iAStorAC.inf" is selected and confirm.
• All of your disks, including the NVMe, will now be listed.
• Delete all of the existing partitions on the NVMe one by one, until only "unallocated free space" remains on the NVMe disk. This will ensure that the standard partitioning task on your future boot disk is done by Windows itself.
• Click "Next" and the installation will continue like normal.
• Do not interrupt this setup routine, except you are asked to confirm or enter information.
• Once the initial setup is complete, wait until Windows has recognized every unknown device and no more additional Windows Updates are available. So, don't start with installing drivers from the Dell Support page or somewhere else before.

In case you need further information about the clean installation method that I used in order to have a stable system just ask  :)