# Understanding cost optimization strategies
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Cost Optimization Hub groups your recommendations into the following cost optimization strategies:

**Purchase Savings Plans**  
Purchase Compute, EC2 instance, and SageMaker Savings Plans.

**Purchase reservations**  
Purchase EC2, Amazon RDS, OpenSearch, Amazon Redshift, ElastiCache, MemoryDB, and DynamoDB reservations.

**Stop**  
Stop idle or unused resources to save up to 100% of the resource cost.

**Delete**  
Delete idle or unused resources to save up to 100% of the resource cost.

**Scale in**  
Scale in idle or unused resources to save on resource costs.

**Rightsize**  
Move to a smaller EC2 instance type of the same CPU architecture.

**Upgrade**  
Move to a later generation product, such as moving from Amazon EBS io1 volume type to io2.

**Migrate to Graviton**  
Move from x86 to Graviton to save costs.

The following table shows the full mapping of recommended actions and resource type.


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[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/cost-management/latest/userguide/coh-optimization-strategies.html)