XPS 8960, 8TB M.2 2280 PCIe NVMe SSD compatible?

Yes you can. The manual max is just what Dell validated oem ssd is up to.

@redxps630​  thank you. Is the process as simple as:

-screwing in the SSD to the slot on the motherboard

-going to disk management and initializing the disk and assigning a drive letter

-formatting it as NTFS?

or is there something I have to do with Windows 11 installation because the Dell OEM Windows possibly limits drives above 4TB? 

If you want to add a second 8TB ssd as drive D: and keep the Dell ssd as Windows 11 boot drive C:, a prerequisite is that you have to switch bios>sata operation mode from Dell default RAID on to AHCI and do this switch in safe mode in order to boot successfully from Dell C: and also see the second 8TB drive in disk mgmt.  after you create new single volume in the 8TB drive it will show up as D:.

this process has nothing to do with 8TB > 4 TB Dell oem “max”.  It is critically dependent on user switching to AHCI in safe mode.  Dell should have written a knowledge article on this as many users would like to add their own secondary drive(s).

https://www.dell.com/community/en/conversations/optiplex-desktops/how-to-safe-boot-after-changing-from-raid-to-ahci/6716d53eb33994192335c92c?keyword=AHCI

https://www.dell.com/support/manuals/en-us/xps-8960-desktop/xps-8960-service-manual/?guid=guid-11d232c8-36fc-412e-91f1-e7fa2851554a&lang=en-us

@redxps630​ after I switch from RAID to AHCI in safe mode, do I add the second 8TB NVMe SSD as drive D: in safe mode? or add it after I reboot in normal mode?

Also, do I leave the bios>sata mode as AHCI or switch it back to RAID after adding the second NVME SSD?

Thanks in advance.

After you switch to AHCI in safe mode (before you add any drive), test you can still boot from Dell boot drive smoothly and also enter bios to confirm it is AHCI.  When these are double checked, you can now add a second ssd or hdd.  Assuming the new drive is unallocated, it would not show in Windows explorer.  You can see the drive in disk mgmt. There you can create a new single volume of the drive (initialize and format: just keep on pressing enter on all default settings). When done the new drive automatically shows up as D: in explorer.  You don’t want to switch back to RAID on.  Just leave bios in AHCI mode.

@redxps630​ when  I type in:

bcdedit /set {current} safeboot minimal​

in the Admin: command prompt it says that 'bcedit" is not recognized as an interal or external command, operable program or batch file. Its windows 11.

@redxps630​ when I type in: bcedit /set {current} safeboot minimal in the admin command prompt, it says that 'bcedit' is not recognized as an interal or external command, operable program or batch file. 

try run command as administrator.

1. Click the Windows Start button
2. Type cmd
3. Right-click on Command Prompt
4. Click Run as administrator

Windows won’t boot in safemode after making the change in cmd prompt as admin.
It says something happened and your PIN isn’t available. When I click to set it up again, the same message pops up and I can’t proceed.

1. ​Run ​​cmd​​ as administrator ​

2. ​Copy-paste this command, which will start Windows in Safe Mode the next time you reboot:​

   ​bcdedit /set {current} safeboot minimal​

3. ​Restart the computer and enter UEFI/BIOS setup.​

4. ​Change the SATA operation mode from RAID to AHCI.​

5. ​Save changes and exit Setup and Windows will automatically boot to Safe Mode.​

6. ​Launch ​​cmd​​ again, as in step #1.​

7. ​Copy-paste this command, which will start Windows in Normal Mode the next time you reboot:​

   ​bcdedit /deletevalue {current} safeboot​

8. ​Reboot and Windows will automatically start with AHCI drivers enabled.​

sounds like you were able to proceed 1-4 but is stuck at step 5

Re: Windows won’t boot in safemode after making the change in cmd prompt as admin.

@redxps630​ i'm stuck after step 2. I tried to boot in safemode before changing from RAID to AHCI and windows won't boot. It says “something happened and your pin isn’t available. Click to set up your pin again”. When I click on “set up my pin” the screen just blinks and nothing happens.

I tried your instructions with advanced options>startup settings>restart but the same thing happens again. 

when you are done with step 2. restart, then press F2 immediately (keep on tapping F2 key while waiting for Dell logo to show up on screen) to enter bios. 

a blue bar should show up at bottom of screen "entering setup" when you see that you can stop tapping F2.

When you enter bios, PC is not going to boot from Windows and ask for PIN during that step.

@redxps630​ so will changing from RAID to AHCI in BIOS solve the problem of the PC not being able to boot from windows and getting stuck on that “set up my PIN” screen?

I do not think Windows asking for PIN has anything to do with RAID to AHCI, as you reported "i'm stuck after step 2" which was before you enter bios to change anything,

If you want to make it easier, boot into Windows and change User Accounts from Microsoft account with password and PIN to local account without password for now (you can always go back to MS account later if you want),