The store you took it to certainly doesn't know their stuff. They must have confused SATA operation settings showing as RAID to actual RAID 0.    RAID in Dell BIOS is the storage controller type that provides better performance with Dell's storage driver. Every manufacturer calls it different, in my Lenovo, instead of the RAID, it says NVME.    Yes, you can reboot to safe mode and uninstall SATA drivers from the device manager. Then you should be able to change the SATA operation from RAID to AHCI. There is still a little chance of boot failure. (not recommended)  If you are planning a simple clone, you don't need to change anything in BIOS. Simply clone and Swap the SSDs. I hope you already have an NVME SSD casing.   Alternately you can do a fresh install of OS on the new SSD, will require bootable Dell  OS USB media     All in All that RAID in bios is not the RAID we all know.  Inspiron 3670 doesn't support RAID.    Any
First, I am just helping a friend who has a Dell Inspiron 3670 desktop he bought about 2 years ago. The desktop came with a 128Gb SSD and a 1Tb HDD and 12GB RAM. He wanted to swap the 128Gb SSD for a 256Gb SSD. When he took it a store they said no can do, it's running RAID. He took it back home and asked me what was up. Since I don't have a Dell, I checked into the Inspiron 6370 and the settings related to RAID. I asked him to check all the related settings and hardware installed. Here is what he has. So this brought up a couple questions. First, why would Dell configure the BIOS with RAID ON when it's never being used for managing drives or Intel Optane memory? Second, can he simply change the BIOS setting to RAID OFF WITHOUT causing any issues with the current Windows 10 install since it appears to have NO function for the current hardware? If he can change the BIOS setting and all boots normally, then he should be able to clone the SSD over to a larger drive and swap it from the current SSD - correct? I've done this many time over the years, literally hundreds of times, without issues. This is the first time though where the BIOS settings implies one thing and the hardware shows something else. Thanks for any help you can give me on this. I just want to make sure a simple answer doesn't cause a huge problem for him.
Inspiron 3670 - Can the RAID "ON" BIOS Setting Be Turned Off