In-memory OLTP (hekaton) is for heavy concurrent load (tens of thousands of concurrent connections with thousands of inserts/sec). The advantage is the lock-less, latch-less optimistic concurrency. It's not a silver bullet for performance in all circumstances.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability