Grok 4 Fast (Reasoning) vs Claude 4.5 Sonnet (thinking)

Detailed comparison of capabilities, features, and performance.

Grok 4 Fast (Reasoning)

Grok 4 Fast (Reasoning)

xAI
VS
Claude 4.5 Sonnet (thinking)

Claude 4.5 Sonnet (thinking)

Anthropic
Feature Grok 4 Fast (Reasoning) Claude 4.5 Sonnet (thinking)
AI Lab xAI Anthropic
Context Size 2,000,000 tokens 1,000,000 tokens
Max Output Size 30,000 tokens 64,000 tokens
Frontier Model Yes Yes
Vision Support No Yes
Description Reasoning-enabled Grok 4 with 2M context. Low latency for time-sensitive tasks and huge context window. The latest Claude 4.5 Sonnet model from Anthropic with maximum reasoning enabled, 200k reasoning tokens in 1M context.

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