Non-Graviton RDS Instance on Eligible Workload

Loïc Fournier

Service Category

Database

Cloud Provider

AWS

Service Name

AWS RDS

Inefficiency Type

Suboptimal Instance Family Selection

Explanation

Many RDS workloads continue to run on older x86 instance types (e.g., db.m5, db.r5) even though compatible Graviton-based options (e.g., db.m6g, db.r6g) are widely available. These newer families deliver improved performance per vCPU and lower hourly costs, yet are often not adopted due to legacy defaults, inertia, or lack of awareness.When workloads are not tightly bound to architecture-specific extensions (e.g., x86-specific binaries or drivers), switching to Graviton typically requires no application changes and results in immediate savings. Persisting with x86 in eligible use cases results in avoidable overpayment for compute.

Relevant Billing Model

RDS is billed per-hour or per-second (depending on engine) based on:

Instance family and size
Storage and backup usage

Graviton-based instances offer 20–40% better price-performance and can lower compute costs significantly for compatible workloads.

Detection

List all active RDS instances and identify those using x86-based families (db.m5, db.r5, etc.)
Cross-reference instance types with available Graviton equivalents for the same engine
Use Compute Optimizer (where available) or performance data to validate compatibility
Identify workloads with steady, general-purpose usage patterns that would benefit from Graviton

Remediation

Evaluate performance requirements and test Graviton-backed RDS instances in staging
Modify instance class to a db.*g Graviton-based equivalent (e.g., db.r6g.large)
Update infrastructure templates (e.g., Terraform, CloudFormation) to default to Graviton where applicable
Revisit instance family selections during each modernization, upgrade, or cost review cycle

Relevant Documentation