September 16, 2025 – Elon Musk’s xAI has unveiled a new addition to its product lineup: the Grok 4 Fast model. This latest offering is now accessible to users via the model selector on the Grok web platform. To use it, users need to activate a newly added toggle switch labeled “early access Beta” in their “subscription settings.”
The standout feature of Grok 4 Fast is its remarkable speed. User reports indicate that it can deliver responses up to ten times faster than the standard Grok 4 model. The key difference between the two lies in Grok 4 Fast’s specialized optimization. It achieves rapid responses by minimizing the time spent on complex tasks. For instance, when asked to generate an SVG image of a robot, Grok 4 Fast intentionally produces a simplified version, reflecting its core principle of prioritizing speed over complexity.
This design approach is particularly beneficial for users who require immediate results, as the model’s swift responses can significantly enhance productivity. However, Grok 4 Fast does have its limitations, especially in scenarios involving creative tasks or those demanding intricate processing. To maintain its high response speed, the model sacrifices some depth and detail in its outputs.
Interestingly, Grok 4 Fast is not entirely new to the public eye. It was previously tested under the codename “Sonoma” on the Arena platform, indicating that xAI had been conducting discreet experiments and refinements before its official launch.
Currently, Grok 4 Fast is still in the “early access” phase. There are indications that it may eventually be made available to free users and could potentially replace the older Grok 3 model.
In addition to introducing Grok 4 Fast, xAI has also added a dedicated “changelog” section to the Grok web platform. This feature provides real-time updates on the product’s development and improvements. Furthermore, there are plans to make Grok 4 Fast compatible with mobile applications in the future.
