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 1,370), while GPT-5.6 Terra leads in SWE-bench software engineering benchmarks (70.4%), while Llama 3.1 405B is more budget-friendly at $3.5/1M per 1M output tokens, while GPT-5.6 Terra provides faster response streaming (128 tok/s). Review the complete breakdown below to determine which model best fits your performance and budget requirements.
10 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.
Meta flagship open-weight 405B dense foundation model with 128k context window.
Currently comparing GPT-5.6 Terra vs Llama 3.1 405B. Alternative family tiers available.
Δ 178 Arena Elo pts
128 tok/s
$3.5 / 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 | Llama 3.1 405B | Advantage Delta |
|---|---|---|---|
| Preference Elo | +178 | ||
| Coding Elo | +157 | ||
| LiveBench | +7.9% | ||
| SWE-bench | +12% | ||
| GPQA Diamond | +6.8% | ||
| Time to first token | +200 ms | ||
| Output speed | 128 tok/s | 42 tok/s | +86 tok/s |
| Input price | $1.25/1M | +$0.25/1M | |
| Output price | $3.5/1M | +$2.5/1M | |
| Context window | +922k |
Simulate monthly production API costs in USD (US Dollar).
Llama 3.1 405B is estimated to save $28.75/month ($345/year).
Higher SWE-bench (70.4%).
Lower output list price ($3.5/1M).
Lower TTFT (160 ms).
Larger window (1.1M).
GPT-5.6 Terra is the side marked multimodal in the catalog.
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | GPT-5.6 Terra | Higher SWE-bench (70.4%). |
| High-volume chat | Llama 3.1 405B | Lower output list price ($3.5/1M). |
| 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 | GPT-5.6 Terra is the side marked multimodal in the catalog. |
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Verified Head-to-Head Telemetry
