KMS 1.0 runs on shared infrastructure. Migrating to a KMS 3.0 instance (software or hardware key management) in the same region gives you higher service quality and better stability.
Considerations
KMS 1.0 and KMS 3.0 differ in features, billing, and instance types. Before migrating, review these differences to determine whether migration fits your workload and, if so, which KMS 3.0 instance type to use.
Evaluate the following:
Benefits of migrating to KMS 3.0
Migration limitations and constraints
Billing changes after migration
KMS 3.0 instance type selection (software vs. hardware key management)