It uses both DDR6 & DDR5. 16GB DDR6 + 2GB DDR5.
I know. most of the builds in this thread also use both. but
someone in this thread thought they were onto something by pointing out that a lot of the builds listed in this thread use DDR5. probably not knowing that the 40 series GPU's have GDDR6. now we come full circle with the Pro also using DDR5
beyond that, it's an interesting choice, and I wonder what they plan on using that 2GB of slower memory for
edit: maybe they'll use the DDR5 for system stuff, so games can use all the GDDR6