Pairwise benchmark snapshot · Aug 16, 2026
In this head-to-head showdown, Grok 4.6 delivers higher overall intelligence and human-preferred responses (Elo 1,592 vs 1,466), while Grok 4.6 leads in SWE-bench software engineering benchmarks (69.1%), while GPT-5.6 Luna is more budget-friendly at $1.2/1M 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
OpenAI 5.6 fast/cheap tier. Official API $0.20/$1.20 per 1M after the Jul 30 80% Luna cut.
xAI Aug 12 2026 post-training refresh of Grok 4.5. Same $2/$6 API price, 500k context, stronger agentic traces.
Currently comparing GPT-5.6 Luna vs Grok 4.6. Alternative family tiers available.
Δ 126 Arena Elo pts
188 tok/s
$1.2 / 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 | Grok 4.6 | Advantage Delta |
|---|---|---|---|
| Preference Elo | +126 | ||
| Coding Elo | +110 | ||
| LiveBench | +7.2% | ||
| SWE-bench | +7.3% | ||
| GPQA Diamond | +9.2% | ||
| Time to first token | +107 ms | ||
| Output speed | 188 tok/s | 118 tok/s | +70 tok/s |
| Input price | +$1.8/1M | ||
| Output price | +$4.8/1M | ||
| Context window | +500k |
Simulate monthly production API costs in USD (US Dollar).
GPT-5.6 Luna is estimated to save $135.00/month ($1,620/year).
Higher SWE-bench (69.1%).
Lower output list price ($1.2/1M).
Lower TTFT (88 ms).
Larger window (1M).
Both accept images. Defaulting to the higher-Elo side (Grok 4.6).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | Grok 4.6 | Higher SWE-bench (69.1%). |
| High-volume chat | GPT-5.6 Luna | Lower output list price ($1.2/1M). |
| Voice / low-latency UI | GPT-5.6 Luna | Lower TTFT (88 ms). |
| Long-document RAG | GPT-5.6 Luna | Larger window (1M). |
| Screenshots / vision | Grok 4.6 | Both accept images. Defaulting to the higher-Elo side (Grok 4.6). |
Brand hub remaps to top xAI vs top OpenAI. After Aug 12 that is Grok 4.6 vs Sol.
xAI’s Aug 12 2026 refresh of Grok 4.5. 500k context. The Grok vs ChatGPT hub remaps here.
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
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