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Grok 4 Fast vs Grok-1.5
Comprehensive side-by-side LLM comparison
Grok 4 Fast leads with 49.8% higher average benchmark score. Grok 4 Fast supports multimodal inputs. Overall, Grok 4 Fast is the stronger choice for coding tasks.
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xAI
Grok 4 Fast is a multimodal language model developed by xAI. It achieves strong performance with an average score of 73.0% across 7 benchmarks. It excels particularly in SimpleQA (95.0%), HMMT 2025 (93.3%), AIME 2025 (92.0%). With a 2.0M token context window, it can handle extensive documents and complex multi-turn conversations. The model is available through 1 API provider. As a multimodal model, it can process and understand text, images, and other input formats seamlessly. Released in 2025, it represents xAI's latest advancement in AI technology.
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xAI
Grok 1.5 was developed by xAI as an advanced language model, designed to provide helpful and accurate information with a focus on reasoning and factual knowledge. Built to serve as a conversational AI with strong analytical capabilities, it represents xAI's early generation of foundation models.
1 year newer
Grok-1.5
xAI
2024-03-28
Grok 4 Fast
xAI
2025-08-28
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Performance Metrics
Context window and performance specifications
Average performance across 1 common benchmarks
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Grok 4 Fast
Average Score:85.7%(+49.8%)
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Grok-1.5
Average Score:35.9%
Provider Availability & Performance
Available providers and their performance metrics
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Grok 4 Fast
1 providers
xAI
Throughput: 90 tok/s
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Grok-1.5
0 providers
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Grok 4 Fast
Avg Score:85.7%(+49.8%)
Providers:1
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Grok-1.5
Avg Score:35.9%
Providers:0