I purchased a Samsung 850 Pro 1tb (MZ7KE1T0BW) to replace the 1tb hdd. with a fast low power Samsung 850 Pro 1tb
when I can I want to replace the mdisk when i can find one on sale.
any advice would be greatly appreciated step by step would even be even beter
Your XPS 15 comes with Dell Backup and Recovery software for creating a recovery drive. But we recommend using a flash drive, not DVDs. This can be used to create an image of the factory hard drive that can be restored to your new SSD.
Since your system drive will be an SSD, you will not need to use the Intel Rapid Start, so turn that off in the BIOS. When you upgrade the mSATA drive, you can use it for backup or storage. This thread provides information on how to disable Intel Rapid Start.
I understand the suggestion of the Flash Drive, but I wanted to have a long term backup of the files and not the risk of somone rewriting the flash drive or breaking it. why the suggestion of the flash drive other than speed. and if you do this, is it like with some brands you can make this file 1 time?
Yes, it's considerably faster and more reliable to use a flash drive. But you have the option of using DVD discs as well.