The vector size limits in AI Search can be found here: https://learn.microsoft.com/en-us/azure/search/vector-search-index-size. Limits are set based not only on technical limitations (depending on the limit) but also based on performance testing. However, to obtain optimal retrieval performance from your RAG app, you can take a look at best practices listed here: https://techcommunity.microsoft.com/t5/ai-azure-ai-services-blog/azure-ai-search-outperforming-vector-search-with-hybrid/ba-p/3929167