Pairwise benchmark snapshot · Aug 17, 2026
In this head-to-head showdown, GPT-5.6 Terra delivers higher overall intelligence and human-preferred responses (Elo 1,548 vs 1,405), while GPT-5.6 Terra leads in SWE-bench software engineering benchmarks (70.4%), while GPT-5.6 Terra is more budget-friendly at $6/1M per 1M output tokens. Review the complete breakdown below to determine which model best fits your performance and budget requirements.
9 benchmarks evaluated across capability, speed, and cost
OpenAI 5.6 mid tier. Official API $2/$12 per 1M after the Jul 30 2026 price cut.
Previous xAI generation before Grok 4. Kept for grok 3 vs grok 4.
Currently comparing GPT-5.6 Terra vs Grok 3. Alternative family tiers available.
Δ 143 Arena Elo pts
128 tok/s
$6 / 1M output
Relative percentile scores computed across all active models in the benchmark catalog.
Comparing top standard models across 6 key capability 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 | GPT-5.6 Terra | Grok 3 | Advantage Delta |
|---|---|---|---|
| Preference Elo | +143 | ||
| Coding Elo | — | — | |
| LiveBench | +8.9% | ||
| SWE-bench | +19% | ||
| GPQA Diamond | +7.8% | ||
| Time to first token | +90 ms | ||
| Output speed | 128 tok/s | 88 tok/s | +40 tok/s |
| Input price | +$2/1M | ||
| Output price | +$9/1M | ||
| Context window | +919k |
Simulate monthly production API costs in USD (US Dollar).
GPT-5.6 Terra is estimated to save $205.00/month ($2,460/year).
Higher SWE-bench (70.4%).
Lower output list price ($6/1M).
Lower TTFT (160 ms).
Larger window (1.1M).
Both accept images. Defaulting to the higher-Elo side (GPT-5.6 Terra).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | GPT-5.6 Terra | Higher SWE-bench (70.4%). |
| High-volume chat | GPT-5.6 Terra | Lower output list price ($6/1M). |
| Voice / low-latency UI | GPT-5.6 Terra | Lower TTFT (160 ms). |
| Long-document RAG | GPT-5.6 Terra | Larger window (1.1M). |
| Screenshots / vision | GPT-5.6 Terra | Both accept images. Defaulting to the higher-Elo side (GPT-5.6 Terra). |
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Verified Head-to-Head Telemetry
