Grok 4.1 Fast vs Llama 3.1 Nemotron Nano 8B

Grok 4.1 Fast

xAI

Grok 4.1 Fast, released by xAI in November 2025, is a fast-response variant from the Grok 4 family featuring a 2M token context window designed for high-throughput applications. It omits thinking tokens for immediate responses, reducing latency while maintaining strong output quality. Grok 4.1 Fast targets production APIs, real-time assistants, and cost-sensitive applications requiring long-context understanding at high volume.

Llama 3.1 Nemotron Nano 8B

NVIDIA

Llama-3.1-Nemotron-Nano-8B-v1 is an 8-billion-parameter model from NVIDIA, developed as a fine-tuned variant of Meta's Llama 3.1 8B using NVIDIA's Nemotron post-training methodology, which applies reinforcement learning and process reward modeling to enhance instruction-following and reasoning capability over the base model. The Nano designation marks it as the entry-level member of the Nemotron family, optimized for efficient inference on a single GPU while delivering meaningfully improved performance on instruction alignment and agentic tasks compared to standard Llama 3.1. Released open-weight on HuggingFace, it is designed for deployment in NVIDIA-accelerated environments and supports NVIDIA NIM for enterprise inference.