Switching M.2 disks around. Is it that simple?

I have two NVMe M.2s, both working beautifully, but one is mounted in a PCIe x4 adapter, and one is mounted in the factory-installed M.2 socket on the board. Because I had the M.2s and the adapter before I got the mounting hardware for the board socket, I went ahead and put the OS and my programs on the M.2 in the adapter-mounted socket, and later, when I got the hardware, I mounted the second disk on the board, and made that one my local storage drive.

I have a vague suspicion that the factory on-board socket might be a better home for my OS and programs, and the PCIe adapter socket might be fine for my local storage (mostly MR images and some stored files, neither of which get accessed very often; no programs and no games).

Whether or not that suspicion is well founded isn't really important. I don't expect to see any performance difference that's measurable, but I'll be happier knowing that the OS is on the board directly, and not on an adapter in a PCIe slot.

So, tonight I'm going to open my case anyway, to pull out my (now completely unused and currently offline) SATA SSDs for use elsewhere, and I'm thinking while I've got 'er open, I might as well physically switch the two M.2 disks.

Yeah, I know I could do it by imaging and restoring and so on without moving the hardware, but this seems much faster and easier.

Is that right? If I switch them and then boot into my UEFI and reset the boot order, will that be it, or am I forgetting something?

I'm unfamiliar with your machine but given it has W11 22H2 on it then it has to be reasonably modern. Given this assumption then I think you just swap your drives and boot up. No need to reset the boot order (if it exists) as the drives will retain their identity and the BIOS / UEFI will find your boot drive and boot your machine.

BobD said:

I'm unfamiliar with your machine but given it has W11 22H2 on it then it has to be reasonably modern. Given this assumption then I think you just swap your drives and boot up. No need to reset the boot order (if it exists) as the drives will retain their identity and the BIOS / UEFI will find your boot drive and boot your machine.

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Yeah, the "compliant" means it's recognized by MS as worthy of 11, without fudging.

I didn't know I didn't have to readjust my boot options in the BIOS, though, That's news I should have known, I guess.

I'm gonna extract the power and data cables from the board, remove the old (NOT!) SSDs, switch the two M.2s, and boot 'er. Thanks for the input.

You will likely have a "boot order" set in the BIOS but you won't have to be concerned with it if things are OK now. The boot order is not based on drive letters nor drive location. It is based on drive content. That is, can it be booted. The drive letters are embedded in the System Volume Information file which exists in the root folder of each drive so they move with your drive. You might be interested in boot order if you wish to boot from external devices. For example, if you want to boot from a USB DVD drive or a USB thumb drive. Even then it is not a big concern. If you access the Advanced Boot Menu ( Google for how or use a shortcut with "C:\Windows\System32\shutdown.exe /r /o /f /t 0" ) then it has an option to boot from USB.

Thank you, my friend. That was good information.

Wisewiz said:

Yeah, the "compliant" means it's recognized by MS as worthy of 11, without fudging.

I didn't know I didn't have to readjust my boot options in the BIOS, though, That's news I should have known, I guess.

I'm gonna extract the power and data cables from the board, remove the old (NOT!) SSDs, switch the two M.2s, and boot 'er. Thanks for the input.

Click to expand...

It seems the old SATA assignation of which port is drive 0 and which is drive 1 does not really apply to nvme drives.

I had an optane drive as drive 0, and an nvme drive as drive 1. I was having software related issues with the optane drive, so I took it out and cloned it to a spare nvme drive, and plugged it in, and it booted fine.

Then I noticed the new OS nvme drive was assigned drive 1, and the original data nvme was assigned drive 0.

I had not changed the data drives position, and I have concluded the old physical port assignations defining drive 0 and 1 do not apply to nvmes in the same way as for SATA drives.

I physically swapped the drives like you are wanting to do, and that swapped the drive assignations so OS was 0 , and data was 1, and it was all fine (the reason I did that was I have batch files that depend on OS being on drive 0 and I did not want to change them).

However, at no point did I go into bios, change boot orders etc.

In simple terms, swap them over if you wish and it should just work.

Good luck.

cereberus said:

In simple terms, swap them over if you wish and it should just work.

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Well, I don't think of myself as being a simple man who needs simple terms but I do thank you, cereberus, for your contribution to my meagre knowledge. It all helps.

It's all done now: the old are out, the new are switched, and I've got to help the missus around the kitchen for a bit before I plug 'er back in and give 'er a try (to be clear, I'm talking about the PC, not the missus). I'm confident that this simple task is going to turn out to have been truly simple. Thanks.

BobD said:

You will likely have a "boot order" set in the BIOS but you won't have to be concerned with it if things are OK now. The boot order is not based on drive letters nor drive location. It is based on drive content. That is, can it be booted. The drive letters are embedded in the System Volume Information file which exists in the root folder of each drive so they move with your drive. You might be interested in boot order if you wish to boot from external devices. For example, if you want to boot from a USB DVD drive or a USB thumb drive. Even then it is not a big concern. If you access the Advanced Boot Menu ( Google for how or use a shortcut with "C:\Windows\System32\shutdown.exe /r /o /f /t 0" ) then it has an option to boot from USB.

Click to expand...

Hi there
slightly incorrect as the boot is done via an EFI file (assuming these are all on GPT disks). The EFI file is stored on an HDD / SSD / NVME device not in the computers BIOS CMOS -- and the default efi file (if more than 1) is set in the CMOS in the computers BIOS parameters. Note not the actual efi file as this is stored on a disk device but the default device id.

The hardware then initiates the boot process which reads the appropriate efi file from the hdd disks on the computer. In the EFI file there's a reference to the UUID of the appropriate boot loader partition which is just the hardware identification of the appropriate "bootable" partition / disk. So these can be swapped around "ad Nauseam" without any problems assuming the appropriate driver. This is also how the boot disk can initiate boot from other Windows systems on other HDD's on the same system.



cheers
jimbo

UPDATE: As per your comments above, @cereberus, the Assigner of Disk Numbers works in very mysterious ways. Now that it's all back together and running, the system disk, which was disk 4 when there were two SATA SSDs and two NVMes, is now (YAY!) disk 0, and the storage disk is disk 1. And that's the way it ought to be. I am happy and pleased and tired, and so I think I'll get ready for bed, and just gloat for a bit about the fact that this simple task worked out so very well. Thanks for the help and support.