Amazon S3 Vectors launched at re:Invent 2025 as a new way to store and query vector embeddings with familiar S3 economics.

But if you're already running OpenSearch for vector search in production, the question is practical: should you migrate, run both, or stay put?

We run OpenSearch-based vector retrieval in a production RAG pipeline. When S3 Vectors launched, we loaded the same dataset into both services and benchmarked them head-to-head: ingestion speed, query latency at p50/p95/p99, cost per million queries, and filtering capabilities.

This lightning talk walks through those results, where each service wins and where it falls short, and closes with a decision flowchart you can apply to your own RAG pipeline. We'll also share a practical pattern for using both services together rather than choosing one.

If you're building RAG on AWS and trying to decide between these two, this talk gives you the numbers so you don't have to run the benchmarks yourself.