Further to the previously mentioned size limitation removal, there have been a number of improvements of the In-Memory OLTP engine that may not be immediately apparent, but can still drastically improve performance and scalability.
First up is a range of improvements to the storage subsystem; not only was the checkpoint file pair limit removed, but there was also the introduction of multi-threaded checkpointing. In SQL Server 2014, the offline checkpoint process was a single-threaded system. This thread would scan the transaction log for changes to memory-optimized tables and write those changes to the checkpoint file pairs. This meant that a potentially multi-core system would have a busy core for the checkpointing process. With SQL Server 2016, this checkpointing system was redesigned to run on multiple threads, therefore increasing throughput to the checkpoint file pairs and thus increasing overall performance and the scalability of the In-Memory...