Grok vs. Pythia

Overview

Grok is the proprietary model family available through xAI's products and API. Grok 4.5 is the current generation, focused on coding, agentic tasks, reasoning, and knowledge work.

xAI introduced Grok in November 2023 and released the weights for Grok-1 under Apache 2.0 in March 2024. Later generations are proprietary and available through Grok, X, and the xAI API. Grok 4.5, released in July 2026, is xAI's current flagship model for software engineering, tool-driven agents, complex reasoning, and professional knowledge work.

Initial release: 2023-11-05

Current generation: Grok 4.5

Reference

https://x.ai/news/grok-4-5

Further Reading

• https://github.com/xai-org/grok-1/tree/main
• https://x.ai/news/grok-4-5

Overview

The most recent (as of May 2023) effort from EleutherAI, Pythia is a set of LLMs trained on The Pile. While it appears to outperform OPT and GPTNeo, its performance against GPT-J is unclear. Versions of Pythia have also been instruct-tuned by the team at Together.

Initial release: 2023-02-13

Reference

https://github.com/EleutherAI/pythia

Further Reading