DDR5 Ram only for AMD?

Let me push this topic to further questions about the DDR5 and the new board :

  1. What about Non-Binary 24 / 48 / 92 GB of RAM ? Will the board be compatible ?
  2. Is the 64Go the maximum limit it will ever have or could it be higher than that with, for example, a futur firmware update ?
  3. What about DDR5-6400 one and up ? Will they be usable with the board ?