Amazon RDS for SQL Server now supports Z1d instances
Starting today, you can now launch Z1d instance types when using Amazon RDS for SQL Server in the following AWS Regions:
US East (N. Virginia), US East (Ohio), US West (Oregon), and US West (N. California).
Europe, Middle East and Africa
EU (Ireland), EU (Frankfurt), and EU (London).
Asia Pacific (Mumbai), Asia Pacific (Seoul), Asia Pacific (Tokyo), Asia Pacific (Singapore), and Asia Pacific (Sydney).
Source:: Amazon AWS