Recent benchmark tests have compared the performance of DocumentDB and MongoDB Atlas, with surprising results. According to the test, MongoDB Atlas sharded cluster achieved a throughput of about 5 times higher than DocumentDB with no shards. Additionally, the CPU usage in DocumentDB was significantly higher due to waiting for IO operations, which could lead to slow processing and outdated data.

The tests also showed that the Kafka lag in the Writer application was much lower when using MongoDB Atlas, taking around 20 minutes compared to DocumentDB's two hours. These results suggest that sharding can greatly improve performance and scalability.

Source: https://dev.to/malaquf/so-long-documentdb-hello-mongodb-atlas-1d14