Comprehensive side-by-side LLM comparison
. Both models have their strengths depending on your specific coding needs.
OpenAI
GPT-5.1 Instant, released by OpenAI in November 2025, is a low-latency variant from the GPT-5.1 family optimized for fast response times and high-throughput workloads. It targets real-time applications, conversational assistants, and production APIs where response speed is a primary requirement alongside GPT-5.1-generation reasoning quality.
xAI
Grok 3, released by xAI in February 2025, is a large language model trained on xAI's Colossus supercluster with substantially increased compute over previous generations. It features a 1M token context window, RL-enhanced Think mode for extended reasoning, and demonstrated strong results on mathematics, coding, and scientific benchmarks. Grok 3 targets complex reasoning, real-time information tasks via X platform integration, and agentic workflows via the xAI API.
8 months newer

Grok 3
xAI
2025-02-17

GPT-5.1 Instant
OpenAI
2025-11
Context window and performance specifications
Available providers and their performance metrics
GPT-5.1 Instant
Grok 3
xAI
GPT-5.1 Instant
Grok 3
GPT-5.1 Instant
Grok 3