Research on Retrieval-Augmented Generation (RAG) demonstrates its significant enhancement of Large Language Models (LLMs) used in generative AI applications by accessing external data, even when information falls within the models' training domain. The study shows that RAG improves the performance of models like GPT-4 by 13% in terms of faithfulness, reducing unhelpful answers by half, and the benefits are even more pronounced for private data inquiries. The research tested RAG at an unprecedented scale with one billion documents, revealing that more data availability for RAG leads to better results. The findings indicate that RAG enables smaller or open-source models like Mixtral and Llama 2 to achieve performance levels comparable to more powerful models, broadening the accessibility of state-of-the-art AI capabilities. Furthermore, combining external and internal knowledge through a classification method enhances response accuracy, with RAG consistently outperforming models' internal knowledge alone. These insights suggest that RAG, by integrating vast data, can democratize access to high-quality generative AI applications, offering flexibility in model choice based on factors like cost and privacy.