Pairwise benchmark snapshot · Aug 16, 2026
In this head-to-head showdown, Claude Opus 4.6 delivers higher overall intelligence and human-preferred responses (Elo 1,574 vs 1,548), while Claude Opus 4.6 leads in SWE-bench software engineering benchmarks (75.9%), while GPT-5.6 Terra is more budget-friendly at $12/1M per 1M output tokens. Review the complete breakdown below to determine which model best fits your performance and budget requirements.
10 direct benchmark disciplines evaluated across capability, speed, and cost
Follow-on Opus release. Slightly behind 4.5 on official SWE-bench bash-only in the last published sweep; stronger multi-step autonomous agent reasoning.
OpenAI 5.6 mid tier. Official API $2/$12 per 1M after the Jul 30 2026 price cut.
Currently comparing Claude Opus 4.6 vs GPT-5.6 Terra. Alternative family tiers available.
Simulate accuracy gains vs added response time & token cost
Reasoning models “think before answering” by generating internal reasoning tokens. Higher effort improves math, coding, and logic accuracy, but increases response delay and token costs.
Δ 26 Arena Elo pts
128 tok/s
$12 / 1M output
Relative percentile scores computed across all active models in the benchmark catalog.
Comparing top Western standard models with China's leading frontier rival across 6 skill dimensions. Tap any spoke or dot to inspect.
Category wins across reasoning intelligence, generation speed, and token cost.
Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy
Generation throughput and time to first token responsiveness
Cost per million tokens and max context window length
| Benchmark | Claude Opus 4.6 | GPT-5.6 Terra | Advantage Delta |
|---|---|---|---|
| Preference Elo | +26 | ||
| Coding Elo | +28 | ||
| LiveBench | +2.9% | ||
| SWE-bench | +5.5% | ||
| GPQA Diamond | +2.8% | ||
| Time to first token | +200 ms | ||
| Output speed | 64 tok/s | 128 tok/s | +64 tok/s |
| Input price | +$13/1M | ||
| Output price | +$63/1M | ||
| Context window | +800k |
Simulate monthly production API costs in USD (US Dollar).
GPT-5.6 Terra is estimated to save $1,400.00/month ($16,800/year).
Higher SWE-bench (75.9%).
Lower output list price ($12/1M).
Lower TTFT (160 ms).
Larger window (1M).
Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.6).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | Claude Opus 4.6 | Higher SWE-bench (75.9%). |
| High-volume chat | GPT-5.6 Terra | Lower output list price ($12/1M). |
| Voice / low-latency UI | GPT-5.6 Terra | Lower TTFT (160 ms). |
| Long-document RAG | GPT-5.6 Terra | Larger window (1M). |
| Screenshots / vision | Claude Opus 4.6 | Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.6). |
Terra is OpenAI’s Sonnet-class invoice. Use it when Sol is too expensive and Luna is too small.
Slightly behind 4.5 on one official SWE-bench sweep; stronger long-horizon traces. We keep the row for old vs URLs.
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