A limited number of Gigabyte's new Z370 motherboards will come with 32GB of Optane built in the board, or at least that is how the PR describes it.
The boards will ship with Gigabyte's M.2 Thermal Guard installed which leads one to surmise that these are not permanently connected to the motherboard similar to how a BGA processor is installed but are instead already installed in an M.2 slot. Regardless of how they attached it, you get the benefits of Optane memory right from the beginning, which is not a bad thing in any way.
This is not their first bundle, you can still grab an Ultra Gaming + 32GB Optane on Amazon, which gives us an idea of the price. Lets hope we don't see branding which describes the board as coming with 32GB of RAM already installed as this could lead to a lot of disappointment for someone who didn't pick up any DDR4.
You can see the effect of using Optane memory on your computer in Ken's review.