Diskbased to in memory tables sql server 2016 ram requirement
Start with the Books Online page on estimating memory requirements for in-memory OLTP. It goes into deep detail, and here's just a snippet:


  When there is an active workload, additional memory is needed to account for row versioning and various operations. How much memory is needed in practice depends on the workload, but to be safe the recommendation is to start with two times the expected size of memory-optimized tables and indexes, and observe what are the memory requirements in practice. The overhead for row versioning always depends on the characteristics of the workload - especially long-running transactions increase the overhead. For most workloads using larger databases (e.g., >100GB), overhead tends to be limited (25% or less).


Keep in mind that that's only for the in-memory OLTP data - not your query workspace, buffer pool for other objects, AG log caching, etc.