Elon Musk’s xAI released Grok 4 Fast on Friday, a streamlined artificial intelligence (AI) model that costs 98% less to run than its predecessor while maintaining similar performance. Artificial Analysis ranked Grok 4 Fast as having the best price-to-performance ratio among publicly available models, operating 47 times cheaper than the original Grok 4. xAI achieved these efficiencies through reinforcement learning techniques that optimize the model’s engagement in complex reasoning versus quick responses. All users, including free accounts, can access Grok 4 Fast through grok.com, iOS, and Android applications starting Saturday. The release followed major staff cuts on September 12. xAI terminated its entire data annotation team, the department that trains AI models.