XPS 8950, Windows 11, make SSD the C: drive?

@liouxsea If you have not looked at Crucial's procedure for installing PCIe NVMe drives here: https://www.crucial.com/support/ssd/ssd-install

I suggest you look at that, especially the part about cloning the original drive using their software.  Basically, you need to clone the original drive and remove the original drive when cloning is completed, then your system should boot from the new drive. In your case, since you are already using your new drive, you should use your 1TB drive to back up the new files you have put on the new drive because the cloning process will wipe the new drive. When you have successfully booted from the new drive you can reinstall the original NVMe drive, boot from the new drive using the F12 Boot Menu, and then reinitialize the original NVMe drive to use for backup. Your original drive serves as a backup if you have a problem with cloning because as long as you identify correctly the source and destination for cloning the original drive is safe. The key to this process to cloning the original drive and then removing it so that the system will boot from the new drive; you don't want two boot drives in the system, otherwise you will have a hard time determining which you are booting from.

Since you have already installed Crucial P3P in the 2nd slot, what you need next is a simple system transfer.

Acronis True Image for Crucial

Download and install it on your main drive C (the old 256G), run Acronis and follow step by step instructions.

After that, shut down the PC and swap the NVME slot to put the new 2T SSD in the slot 1 (the one closer to CPU), you can either put the old 256G in slot 2 or leave the slot for another bigger SSD.

Done.

Gathering the information from OP post:

"I already initialized and named it and have changed my settings to have new files save to it."

"Currently I am still forced to stop doing whatever I am doing and then manually move things (or copy) to the new drive and then I have to go back and then delete the original version"

I think that the files settings may have been done incorrectly.  Since they are both solid state drives and having similar performance, the least effort configuration to keep both drives would be using the small drive for boot and programs and the larger one for files (data).  To do that, just verifying the existing configurations and making correction to match basic guideline below.

Make sure to have all your data backup prior to any drive configurations.

Open Settings >  System >  Storage >  Advanced storage settings >  Where new content is saved, change everything to drive D (larger drive), except for New apps will save to, keep it in drive C (smaller drive).  Using File Explorer, navigate to drive D and verify all folders have been created inside a user folder, adding Downloads folder by create new folder and any personalized folder to match the same folders being used in drive C.

Open File Explorer, arrange and organize often used folders such as:  Documents, Downloads, Music, Pictures, Videos, and any personalized created folders, right click on a folder and select properties >  Location >  Move >  then browse the dialog box to the same folder name in drive D and select Apply.  Any folder that has stored data will start to move to drive D.  When it complete, do this (move) to each folder.

When complete, there should not be any data left on drive C.  All programs (no game) for an average user would be around 100 GB, more or less.  Open each web browser(s) and any download utilities, setting the down load location to Downloads folder in drive D.

Reboot system and testing by download or copying data to the system.  Verifying if they are added to drive D.

Since this is new, easiest solution would be to remove the OEM NVME, put the new one in and use the dell recovery (via online) to reinstall the windows. 

It will recreate all the paritions including the OS recovery parition (After you run Dell update and Support Assist). Afterwards, reinstall the Original NVME, choose the correct one to boot to, copy all the files you need to the new SSD. If you don't care for the factory image and stuff in the original drive, remove all partitions and re-initialize a single primiary parition.

I know there's a lot of steps I've not gone into detals but this is the jist of it.

My XPS8950, purchased in early 2022 had a KIOXA 1TB SSD when shipped.

This was exactly 1TB with a capacity of 1024GB. So I Satisfied with the performance of this SSD, I bought retail KIOXA EXCERIA PRO 1TB-SSD.

I was curious about the difference between SSD-0 and SSD-1 (near the DIMMs), and cloned the boot SSD after confirming there was no significant difference in performance.

The advantage of SSD-1, which is close to DIMM, is that it can be fitted with a large heatsink. I decided to put the hotter boot SSD on SSD-1.

I put the 10GbE card on the PCIe x4 sandwiched between the CPU and the RTX3080, so I can only use a thin heatsink for the SSD-0 hidden underneath. I use it as a data drive.

It may be a minor issue, but KIOXA firmware for B2B devices is provided by Dell and retail KIOXA firmware is provided by Toshiba.

As a boot drive, I think an SSD that allows settings such as Over-Provisioning is more convenient ?

You added a PCIe card for more m.2 drives or did I misunderstand the 10gbe card and it's a network card?

From the one closest to the CPU, Intel X550-T2 (10GbEx2port) and RTX3080. (If you don't need 2port 10GbE, i recommend Marvell AQC113CS NIC)

SSD-0 is tucked under the NIC by Dell system designers, but they all run crazy hot. So I moved the M.2 for booting to the SSD-2, which is easier to cool.

As a result, the temperature difference between the two KIOXA M.2 drives of the same model reached 15℃!

That is what I ended up doing. I tried to do it without Acronis at first and just copying each file folder manually. What a waste of time that was.  Then I got stuck on this repair loop.  In the end what you said to do is what worked out. I did end up physically switching the drive locations, which I think in hindsight I should of just let them be where they were. But I do now  have my crucial as my C drive and my original m2 as my E drive.  Cloning with Acronis was for sure the best way to achieve this.

I now however have a new issue with Windows 11 telling me I need a product key to activate it, something about using  a different email than before....Aye aye aye...but I'll manage that. 

If only I would of checked the replies before embarking on my drive switching journey , I would have saved hours of useless booting. 

Good it worked out.  What a positive surprise is there is no need to boot from USB-drive as it is usually required.  I don't bother to find out why.