xAI: Grok 4 Fast

xAI's Grok 4 Fast, released on September 18, 2025, is a multimodal model featuring a substantial 2 million token context window and a focus on cost-efficiency. It offers both non-reasoning and reasoning capabilities, configurable via API. In terms of overall performance, Grok 4 Fast demonstrates moderate speed, ranking in the 25th percentile across benchmarks, indicating it performs adequately but not among the fastest models. Its pricing is competitive, placing it in the 43rd percentile. A significant strength is its exceptional reliability, achieving a perfect 100% success rate across all benchmarks, signifying consistent and dependable operation with minimal technical failures. Analyzing benchmark results, Grok 4 Fast excels in the Ethics (Baseline) category, achieving perfect 100% accuracy. This makes it the most accurate model at its price point and among models of comparable speed for ethical reasoning tasks. In Coding (Baseline), it performs strongly with 94.0% accuracy, placing it in the 89th percentile. While its accuracy is high, the duration for coding tasks is in the 22nd percentile, suggesting it is not the fastest for these complex computations. Overall, Grok 4 Fast's key strengths lie in its high accuracy across diverse categories, particularly in ethics, and its outstanding reliability. Its primary area for improvement is speed, where it performs moderately.