Suboptimal Architecture Configuration for Lambda Functions

Shireen Maini

Service Category

Compute

Cloud Provider

AWS

Service Name

AWS Lambda

Inefficiency Type

Suboptimal Configuration

Explanation

While many AWS customers have migrated EC2 workloads to Graviton to reduce costs, Lambda functions often remain on the default x86 architecture. AWS Graviton2 (ARM) offers lower pricing and equal or better performance for most supported runtimes — yet adoption remains uneven due to legacy defaults or lack of awareness. Continuing to run eligible Lambda functions on x86 leads to unnecessary spending. The migration requires minimal configuration changes and can be verified through benchmarking and workload testing.

Relevant Billing Model

Lambda is billed based on:

Number of invocations
Duration (per millisecond) multiplied by memory configured
Architecture — Graviton functions are ~20% cheaper than x86 equivalents

If a function continues to use x86 when it could run on ARM, the result is higher cost for equivalent workload performance.

Detection

Review Lambda function configurations to identify functions using x86_64 architecture
Cross-reference with supported runtimes to determine Graviton compatibility
Use AWS Lambda Power Tuning or performance benchmarking to validate migration feasibility
Look for high-frequency functions with stable workloads that would benefit most from architecture optimization

Remediation

Update Lambda function configurations to use ARM/Graviton2 where compatible
Benchmark function performance and duration to validate equal or improved performance
For stable, high-throughput functions, consider pairing architecture changes with Compute Savings Plans
Incorporate architecture selection into CI/CD pipelines to ensure consistency going forward

Relevant Documentation