Model comparison
Llama 3.1 405B vs o3
Head-to-head evidence from 11 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Llama 3.1 405B #102 (Estimated); o3 #131 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Llama 3.1 405B and o3 share 11 comparable benchmark results. 0 of 8 categories are comparable. 0 results are unique to Llama 3.1 405B; 5 to o3.
Updated July 22, 2026- Shared results
- 11
- Llama 3.1 405B only
- 0
- o3 only
- 5
- Comparable categories
- 0 / 8
Benchmark data for Llama 3.1 405B and o3 is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 11 shared benchmark results across 5 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 is priced at $2.00 input / $8.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for Llama 3.1 405B. o3 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 |
|---|---|---|---|
| Math | Llama 3.1 405BNot measured | MarginNo overlap | o314.5 |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Llama 3.1 405B | o3 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Llama 3.1 405B$0 input / $0 output | o3$2 input / $8 output | Llama 3.1 405B has the lower combined listed price. |
| Generation speedtokens per second | Llama 3.1 405B29 tok/s | o3118 tok/s | o3 has the higher measured throughput. |
| First-answer latencyseconds to first token | Llama 3.1 405B2.19 s | o35.38 s | Llama 3.1 405B reaches the first token sooner. |
| Context windowmaximum listed tokens | Llama 3.1 405B128K | o3200K | o3 lists the larger context window. |
Benchmark Deep Dive
Agentic1 benchmarks
| Benchmark | Llama 3.1 405B | o3 | Result |
|---|---|---|---|
| τ²-bench resultsSource | 19% | 80.7% | o3 leads |
Coding1 benchmarks
| Benchmark | Llama 3.1 405B | o3 | Result |
|---|---|---|---|
| AA-SciCodeSource | 29.9% | 41.0% | o3 leads |
Reasoning2 benchmarks
Knowledge6 benchmarks
| Benchmark | Llama 3.1 405B | o3 | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 8.5% | 30.4% | o3 leads |
| AA-GPQA DiamondSource | 51.5% | 82.7% | o3 leads |
| AA-HLESource | 4.2% | 20.0% | o3 leads |
| AA-Omniscience IndexSource | -17.3% | -15.3% | o3 leads |
| AA-Omniscience AccuracySource | 22.3% | 38.4% | o3 leads |
| AA-Omniscience Hallucination RateSource | 51.0% | 87.1% | Llama 3.1 405B leads |
Math3 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | Llama 3.1 405B | o3 | Result |
|---|---|---|---|
| AA-IFBenchSource | 39.0% | 71.4% | o3 leads |
Frequently Asked Questions (3)
Can I compare Llama 3.1 405B and o3 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 today?
Llama 3.1 405B: $0.00 input / $0.00 output per 1M tokens o3: $2.00 input / $8.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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