Model Comparison
GPT-5.1 Codex (High)
vs. Claude Opus 5.5 (Xhigh, Default Fallback)
GPT-5.1 Codex (High) has not been available at LLMBase since 26 October 2026. Open alternative: Qwen3 Coder →
Claude Opus 5.5 (Xhigh, Default Fallback) has not been available at LLMBase since 26 October 2026. Open alternative: DeepSeek V4 Pro →
Comparing 2 AI models · 0 benchmarks · OpenAI, Anthropic
Recommended Pick
OpGPT-5.1 Codex (High)6 metric winsStrongest on: Input price, Output price, Blended price
Lowest Price
GPT-5.1 Codex (High)
$1.25/1M input price
Differences That Matter
Price gap
GPT-5.1 Codex (High) is 3.2x cheaper on input tokens than Claude Opus 5.5 (Xhigh, Default Fallback).
Speed gap
GPT-5.1 Codex (High) generates about 1.5x as many tokens per second as Claude Opus 5.5 (Xhigh, Default Fallback).
Top-pick rationale
GPT-5.1 Codex (High) wins 6 measurable categories, including Input price, Output price, Blended price, Throughput.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
GPT-5.1 Codex (High)
OpenAI
TTFT
—
Time
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tok/s
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Tokens
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Cost
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Claude Opus 5.5 (Xhigh, Default Fallback)
Anthropic
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
EU-hosted open models, one API
Servers in Germany & Finland. Operated by a German company under the GDPR, DPA available, ISO 27001-certified data centres.
Full Comparison
| Metric | Top Pick Op GPT-5.1 Codex (High) | An Claude Opus 5.5 (Xhigh, Default Fallback) |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $1.25/1M | $4.00/1M |
| Output Cost | $10.00/1M | $20.00/1M |
| Blended (3:1) | $3.44/1M | $8.00/1M |
| Specifications | ||
| Organization | OpenAI | Anthropic |
| Release Date | Nov 13, 2025 | Sep 22, 2026 |
| Performance & Speed | ||
| Throughput | 127.0 tok/s | 84.1 tok/s |
| TTFT | 8180ms | 157490ms |
| Latency | 8180ms | 157490ms |
| Composite Indices | ||
| Value Score | — | 100.0 |
| Reasoning Score | — | 57.0 |
| Intelligence | — | 57.0 |
Key Takeaways
GPT-5.1 Codex (High) offers the best value at $1.25/1M,making it ideal for high-volume applications and cost-conscious projects.
All models support context windows of ∞+ tokens,suitable for processing lengthy documents and maintaining extended conversations.
When to Choose Each Model
GPT-5.1 Codex (High)
- Cost-sensitive applications
- High-volume processing
Claude Opus 5.5 (Xhigh, Default Fallback)
- General-purpose AI
- Versatile applications
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