Model comparison
Llama 3.1 405B vs o3-mini
Head-to-head evidence from 5 shared benchmark results across 3 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Llama 3.1 405B #107 (Estimated); o3-mini #141 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Llama 3.1 405B and o3-mini share 5 comparable benchmark results. 0 of 8 categories are comparable. 6 results are unique to Llama 3.1 405B; 5 to o3-mini.
Updated July 24, 2026- Shared results
- 5
- Llama 3.1 405B only
- 6
- o3-mini only
- 5
- Comparable categories
- 0 / 8
Benchmark data for Llama 3.1 405B and o3-mini is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 5 shared benchmark results across 3 evidence categories; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.
o3-mini is priced at $1.10 input / $4.40 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for Llama 3.1 405B. o3-mini has the larger context window at 200K, compared with 128K for Llama 3.1 405B.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Llama 3.1 405B | Δ | o3-mini |
|---|---|---|---|
| Coding | Llama 3.1 405BNot measured | MarginNo overlap | o3-mini49.3 |
| Knowledge | Llama 3.1 405BNot measured | MarginNo overlap | o3-mini77.2 |
| Inst. Following | Llama 3.1 405BNot measured | MarginNo overlap | o3-mini93.9 |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Llama 3.1 405B | o3-mini | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Llama 3.1 405B$0 input / $0 output | o3-mini$1.1 input / $4.4 output | Llama 3.1 405B has the lower combined listed price. |
| Generation speedtokens per second | Llama 3.1 405B29 tok/s | o3-mini160 tok/s | o3-mini has the higher measured throughput. |
| First-answer latencyseconds to first token | Llama 3.1 405B2.19 s | o3-mini7.12 s | Llama 3.1 405B reaches the first token sooner. |
| Context windowmaximum listed tokens | Llama 3.1 405B128K | o3-mini200K | o3-mini lists the larger context window. |
Benchmark Deep Dive
Agentic1 benchmarks
| Benchmark | Llama 3.1 405B | o3-mini | Result |
|---|---|---|---|
| τ²-bench resultsSource | 19% | 28.7% | o3-mini leads |
Coding2 benchmarks
Reasoning2 benchmarks
Knowledge8 benchmarks
| Benchmark | Llama 3.1 405B | o3-mini | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 8.5% | 19.0% | o3-mini leads |
| AA-GPQA DiamondSource | 51.5% | 74.8% | o3-mini leads |
| AA-HLESource | 4.2% | 8.7% | o3-mini leads |
| AA-Omniscience IndexSource | -17.3% | — | Not comparable |
| AA-Omniscience AccuracySource | 22.3% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 51.0% | — | Not comparable |
| MMLUSource | — | 86.9% | Not comparable |
| GPQASource | — | 77.2% | Not comparable |
Math1 benchmarks
| Benchmark | Llama 3.1 405B | o3-mini | Result |
|---|---|---|---|
| AIME 2024Source | — | 87.3% | Not comparable |
Frequently Asked Questions (3)
Can I compare Llama 3.1 405B and o3-mini on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for Llama 3.1 405B and o3-mini today?
Llama 3.1 405B: $0.00 input / $0.00 output per 1M tokens o3-mini: $1.10 input / $4.40 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.