XPS 8700, installing SSD

Does your PC already have a 32-GB SSD that's used as a system cache? If it does, you're going to have to break the cache before you do anything else. Otherwise Windows on the HDD will become unbootable, requiring a complete reinstall. And then you would have to change BIOS from RAID to AHCI, but this has to be done the right way too, or Windows will be unbootable. So important to know if you have the mSATA cache or not...

What kind of SSD did you get, SATA or mSATA and what storage capacity?

An mSATA SSD just plugs into a motherboard connector so doesn't need any extra hardware.

For a SATA SSD, you need to buy:
One SATA data cable
One tray (caddie) to mount a 2.5" SATA SSD in a 3.5" drive bay
Mounting screws to secure the tray in a 3.5" drive bay

Read the Service Manual for instructions.

Then you can clone the HDD onto the new SSD so you don't have to reinstall everything. You can use Macrium Reflect (free)...

Probably need this to convert MSATA to 2.5 drive and provide a way to format it with diskpart.

https://www.amazon.com/Sabrent-2-5-Inch-Aluminum-Enclosure-Adapter/dp/B08P7WS899/

and this

https://www.amazon.com/SilverStone-SDP09-2-5-Inch-3-5-Inch-Hot-Swappable/dp/B0049MPQDG/

HOWEVER the Msata is limited to 512 GIG Max

Do not be fooled by QLC drives (Dogfish Msata)that are larger because they have VERY limited durability. Actually have only 1 or 2 total chips on them vs 4 or more for samsung 850 evo  SLC drives (Samsung PRO) have 100,000 cycles  MLC drives have 10,000 cycles,  TLC Drives have 3000 cycles,  QLC Drives have 1000 cycles max and they are DEAD.

https://www.amazon.com/Drive-mSATA-V-NAND-Retail-Packaging/dp/B089SQGW74/

If you want 1 TB or more go for a 2.5 drive instead thats TLC or better.

USB Dock should be used to recover your data.

Apps will need to be reinstalled.

https://www.amazon.com/SilverStone-Technology-External-Supports-TS12C/dp/B071J6TYSP/

Re: I recently decided to order a SSD, make that my primary boot drive, and make the HDD my secondary data drive.  What do I need to make this work? Do I need mounting kit? Additional SATA cable(s)

the optional small 32gb mSATA that came with some 8700 is too small by 2021 standard. Minimum primary boot ssd size ought to be 128-256 Gb now. If you have ordered a 2.5” sata ssd from Dell, you need a 2.5 to 3.5 adapter.  8700 has option to mount up to three 3.5” drives.  Check manual. Yes, you need another sata data cable.

If you currently do not have mSATA installed, then clone OS from 1TB hdd to new ssd, or do a fresh install of OS on new ssd.  fresh install is easier.

if you have mSATA installed, you can either uninstall it or disable raid on it and 1TB hdd, which was referred as breaking the raid in 1st reply.  for user not familiar w raid, just uninstall the mSATA and change bios sata mode to ACHI, which was already suggested.

after installing os on new ssd, delete partition on 1TB hdd and format it to make a clean data drive.

@gtifeld123  You have to break the cache before you uninstall the mSATA drive, if one is installed, not the other way around.