Model Comparison
Grok 4.1 Fast (Reasoning)
vs. GPT-5.5 (xhigh)
Comparing 2 AI models · 10 benchmarks · xAI, OpenAI
Recommended Pick
Op GPT-5.5 (xhigh) 11 metric wins Strongest on: Throughput, Reasoning, Intelligence
Lowest Price
Grok 4.1 Fast (Reasoning)
$0.00/1M input price
Best Reasoning
GPT-5.5 (xhigh)
66.0 reasoning score
Blends available reasoning benchmarks
Best for Coding
GPT-5.5 (xhigh)
59.1 coding index
Composite Indices
Higher is better; speed and price are normalized
Standard Benchmarks
Only benchmarks with data are shown
Differences That Matter
Price gap
Grok 4.1 Fast (Reasoning) is ∞x cheaper on input tokens than GPT-5.5 (xhigh).
Reasoning gap
GPT-5.5 (xhigh) leads Grok 4.1 Fast (Reasoning) by 2.0 points on reasoning.
Coding gap
GPT-5.5 (xhigh) leads Grok 4.1 Fast (Reasoning) by 28.2 points on coding.
Top-pick rationale
GPT-5.5 (xhigh) wins 11 measurable categories, including Throughput, Reasoning, Intelligence, Coding.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
Grok 4.1 Fast (Reasoning)
xAI
TTFT
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Time
—
tok/s
—
Tokens
—
Cost
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GPT-5.5 (xhigh)
OpenAI
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
Full Comparison
| Metric | xA Grok 4.1 Fast (Reasoning) | Top Pick Op GPT-5.5 (xhigh) |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $0.00/1M | $5.00/1M |
| Output Cost | $0.00/1M | $30.00/1M |
| Blended (3:1) | — | $11.25/1M |
| Specifications | ||
| Organization | xAI | OpenAI |
| Release Date | Nov 19, 2025 | Apr 23, 2026 |
| Performance & Speed | ||
| Throughput | — | 66.5 tok/s |
| TTFT | — | 43813ms |
| Latency | — | 43813ms |
| Composite Indices | ||
| Value Score | — | 100.0 |
| Reasoning Score | 64.0 | 66.0 |
| Intelligence | 38.6 | 60.2 |
| Coding | 30.9 | 59.1 |
| Math | 89.3 | — |
| Standard Benchmarks | ||
| GPQA | 85.3% | 93.5% |
| MMLU Pro | 85.4% | — |
| HLE | 17.6% | 44.3% |
| LiveCodeBench | 82.2% | — |
| AIME 2025 | 89.3% | — |
| SciCode | 44.2% | 56.1% |
| LCR | 68.0% | 74.3% |
| IFBench | 52.7% | 75.9% |
| TAU-bench v2 | 93.3% | 93.9% |
| TerminalBench Hard | 24.2% | 60.6% |
Key Takeaways
Grok 4.1 Fast (Reasoning) offers the best value at $0.00/1M, making it ideal for high-volume applications and cost-conscious projects.
GPT-5.5 (xhigh) has the strongest reasoning profile with a 66.0 reasoning score, combining the available reasoning-heavy benchmarks.
GPT-5.5 (xhigh) reaches a 59.1 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
Grok 4.1 Fast (Reasoning)
- Cost-sensitive applications
- High-volume processing
GPT-5.5 (xhigh)
- Complex reasoning tasks
- Research & analysis
- Code generation
- Software development
