Pairwise benchmark snapshot · Aug 16, 2026
In this head-to-head showdown, Seed 2.1 Turbo delivers higher overall intelligence and human-preferred responses (Elo 1,472 vs 1,466), while Seed 2.1 Turbo leads in SWE-bench software engineering benchmarks (63.2%), while Seed 2.1 Turbo is more budget-friendly at $1.1/1M per 1M output tokens, while GPT-5.6 Luna provides faster response streaming (188 tok/s). 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
OpenAI 5.6 fast/cheap tier. Official API $0.20/$1.20 per 1M after the Jul 30 80% Luna cut.
ByteDance Seed 2.1 Turbo, listed on public model timelines as an Aug 10 2026 API drop.
Currently comparing GPT-5.6 Luna vs Seed 2.1 Turbo. Alternative family tiers available.
Δ 6 Arena Elo pts
188 tok/s
$1.1 / 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 | GPT-5.6 Luna | Seed 2.1 Turbo | Advantage Delta |
|---|---|---|---|
| Preference Elo | +6 | ||
| Coding Elo | +22 | ||
| LiveBench | +0.6% | ||
| SWE-bench | +1.4% | ||
| GPQA Diamond | +1.4% | ||
| Time to first token | +32 ms | ||
| Output speed | 188 tok/s | 160 tok/s | +28 tok/s |
| Input price | $0.27/1M | +$0.07/1M | |
| Output price | +$0.1/1M | ||
| Context window | +744k |
Simulate monthly production API costs in USD (US Dollar).
GPT-5.6 Luna is estimated to save $0.95/month ($11/year).
Higher SWE-bench (63.2%).
Lower output list price ($1.1/1M).
Lower TTFT (88 ms).
Larger window (1M).
Both accept images. Defaulting to the higher-Elo side (Seed 2.1 Turbo).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | Seed 2.1 Turbo | Higher SWE-bench (63.2%). |
| High-volume chat | Seed 2.1 Turbo | Lower output list price ($1.1/1M). |
| Voice / low-latency UI | GPT-5.6 Luna | Lower TTFT (88 ms). |
| Long-document RAG | GPT-5.6 Luna | Larger window (1M). |
| Screenshots / vision | Seed 2.1 Turbo | Both accept images. Defaulting to the higher-Elo side (Seed 2.1 Turbo). |
Listed on public model timelines as an Aug 10 2026 API drop. Preview-quality story, indexable because we have a full snapshot.
Luna is the OpenAI fast/cheap 5.6 SKU after Jul 30. It is not Sol. Sort by price and TTFT, not Elo.
High-volume agents that cannot pay Sol. Compare to Luna before you assume the new cheap SKU wins.
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Verified Head-to-Head Telemetry
