Pairwise benchmark snapshot · Aug 16, 2026
In this head-to-head showdown, Claude Opus 4.8 delivers higher overall intelligence and human-preferred responses (Elo 1,598 vs 1,548), while Claude Opus 4.8 leads in SWE-bench software engineering benchmarks (78.4%), 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.
9 direct benchmark disciplines evaluated across capability, speed, and cost
Prior Opus generation still billed at $5/$25. Kept as a compare baseline against Opus 5.
OpenAI 5.6 mid tier. Official API $2/$12 per 1M after the Jul 30 2026 price cut.
Currently comparing Claude Opus 4.8 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 50 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 4.8 | GPT-5.6 Terra | Advantage Delta |
|---|---|---|---|
| Preference Elo | +50 | ||
| Coding Elo | +62 | ||
| LiveBench | +4.5% | ||
| SWE-bench | +8% | ||
| GPQA Diamond | +4.2% | ||
| Time to first token | +170 ms | ||
| Output speed | 66 tok/s | 128 tok/s | +62 tok/s |
| Input price | +$3/1M | ||
| Output price | +$13/1M | ||
| Context window | — |
Simulate monthly production API costs in USD (US Dollar).
GPT-5.6 Terra is estimated to save $300.00/month ($3,600/year).
Higher SWE-bench (78.4%).
Lower output list price ($12/1M).
Lower TTFT (160 ms).
Larger window (1M).
Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.8).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | Claude Opus 4.8 | Higher SWE-bench (78.4%). |
| 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 | Claude Opus 4.8 | Larger window (1M). |
| Screenshots / vision | Claude Opus 4.8 | Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.8). |
Terra is OpenAI’s Sonnet-class invoice. Use it when Sol is too expensive and Luna is too small.
Opus 4.8 still bills $5/$25. We keep it so Opus 5 vs 4.8 is a real generation delta, not marketing.
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