Model Comparison
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback)
vs. Grok 4.3 (low)
Comparing 2 AI models · 7 benchmarks · Anthropic, xAI
Recommended Pick
An Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback) 11 metric wins Strongest on: TTFT, Latency, Reasoning
Best Value
Grok 4.3 (low)
100.0 value score
45.7 reasoning / $1.56/1M
Lowest Price
Grok 4.3 (low)
$1.25/1M input price
Best Reasoning
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback)
68.6 reasoning score
Blends available reasoning benchmarks
Best for Coding
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback)
62.0 coding index
Composite Indices
Higher is better; speed and price are normalized
Standard Benchmarks
Only benchmarks with data are shown
Differences That Matter
Best value
Grok 4.3 (low) has the strongest quality-to-price mix at 100.0 out of 100 value points.
Price gap
Grok 4.3 (low) is 8.0x cheaper on input tokens than Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback).
Reasoning gap
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback) leads Grok 4.3 (low) by 22.9 points on reasoning.
Coding gap
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback) leads Grok 4.3 (low) by 30.4 points on coding.
Top-pick rationale
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback) wins 11 measurable categories, including TTFT, Latency, Reasoning, Intelligence.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback)
Anthropic
TTFT
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Time
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tok/s
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Tokens
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Cost
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Grok 4.3 (low)
xAI
TTFT
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Time
—
tok/s
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Tokens
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Cost
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Which answer was more useful?
Full Comparison
| Metric | Top Pick An Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback) | xA Grok 4.3 (low) |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $10.00/1M | $1.25/1M |
| Output Cost | $50.00/1M | $2.50/1M |
| Blended (3:1) | $20.00/1M | $1.56/1M |
| Specifications | ||
| Organization | Anthropic | xAI |
| Release Date | Jun 9, 2026 | Apr 30, 2026 |
| Performance & Speed | ||
| Throughput | — | 145.5 tok/s |
| TTFT | — | 5030ms |
| Latency | — | 5030ms |
| Composite Indices | ||
| Value Score | 11.7 | 100.0 |
| Reasoning Score | 68.6 | 45.7 |
| Intelligence | 59.9 | 35.4 |
| Coding | 62.0 | 31.6 |
| Standard Benchmarks | ||
| GPQA | 92.6% | 84.3% |
| HLE | 53.3% | 17.3% |
| SciCode | 60.2% | 41.9% |
| LCR | 70.0% | 64.0% |
| IFBench | 63.5% | 81.0% |
| TAU-bench v2 | 98.5% | 88.9% |
| TerminalBench Hard | 62.9% | 26.5% |
Key Takeaways
Grok 4.3 (low) offers the best value at $1.25/1M, making it ideal for high-volume applications and cost-conscious projects.
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback) has the strongest reasoning profile with a 68.6 reasoning score, combining the available reasoning-heavy benchmarks.
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback) reaches a 62.0 coding index, making it the top choice for software development and code generation tasks.
All models support context windows of ∞+ tokens, suitable for processing lengthy documents and maintaining extended conversations.
When to Choose Each Model
Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback)
- Complex reasoning tasks
- Research & analysis
- Code generation
- Software development
Grok 4.3 (low)
- Cost-sensitive applications
- High-volume processing
