Storage Replica (SR): If the latency between volumes < 5ms, Storage Replica supports synchronous replication (no data loss).
Storage Replica supports asynchronous replication for longer ranges and higher latency networks. Storage Replica asynchronous replication is not checkpoint-based but instead replicates continuously. This way data loss is kept to a minimum (seconds to minutes).
Hyper-V Replica (HR): With Hyper-V Replica replication frequency can be set to 30 seconds, 5 minutes, or 15 minutes on a per-VM basis.
Microsoft, S2D [SDS]/2.0, Datacenter
Remote Replication Frequency, Disaster Recovery, Data Availability