I have a z270 msi pc mate board with 7700K...
and before you even ask, I have the latest bios.
looked a video on youtube about Optane memory... and decided to buy...
but the video, and the outside of the box did not say anything
about the crazy requirements.
I opened the Box, and surprise... I need Windows 10.
Thanks for taking the time to post about your Intel® Optane™ Technology experience and to provide a solution as well.
You may have found this "https://www.intel.com/content/www/us/en/support/memory-and-storage/intel-optane-memory/000023994.html before you buy Intel® Optane™ Memory" link where it shows the requirements needed to use this technology and it does require GPT partition.
If you want to keep your configuration and it works that's fine, it may also help some other customers.