Pairwise benchmark snapshot · Aug 16, 2026

Llama 3.1 405B vs OpenAI: o3 Mini benchmark

Name: Llama 3.1 405B vs OpenAI: o3 Mini AI benchmark comparison
Creator: CompareLLM
License: https://creativecommons.org/licenses/by/4.0/

This page compares Llama 3.1 405B (Meta) and OpenAI: o3 Mini (OpenAI) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, OpenAI: o3 Mini is ahead by 190 points (1,560 vs 1,370; seed-bootstrap (Aug 1, 2026)). On SWE-bench coding, OpenAI: o3 Mini resolves 78.5% versus 58.4% (seed-bootstrap (Aug 1, 2026)). OpenAI: o3 Mini streams faster (92 tok/s) while Llama 3.1 405B is the cheaper output token ($3.5/1M). OpenAI: o3 Mini has the larger context window (200k tokens). Every cell below is a dated snapshot from a named public source — we do not invent missing scores, and we do not run SWE-bench ourselves.

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Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Llama 3.1 405B (1)vsOpenAI: o3 Mini (9)

Llama 3.1 405B: 1W (10%)Overall: OpenAI: o3 MiniOpenAI: o3 Mini: 9W (90%)

← Llama 3.1 405BOpenAI: o3 Mini →

OpenAI: o3 Mini (5/5)

Intelligence & Reasoning

Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy

Preference Elo

1,370vs1,560

Coding Elo

1,385vs1,585

SWE-bench

58.4%vs78.5%

LiveBench

61.2%vs72.4%

GPQA Diamond

75.2%vs87.2%

Llama 3.1 405B: 0WOpenAI: o3 Mini: 5W

OpenAI: o3 Mini (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

42 tok/svs92 tok/s

Time to first token

360 msvs290 ms

Llama 3.1 405B: 0WOpenAI: o3 Mini: 2W

OpenAI: o3 Mini (2/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$3.5/1Mvs$4.4/1M

Input price

$1.25/1Mvs$1.1/1M

Context window

128kvs200k

Llama 3.1 405B: 1WOpenAI: o3 Mini: 2W

Capability Matchup Radar

Multi-Dimensional Capability Radar

Each spoke is a skill. Farther from the center is better (0–100th percentile). Tap any dot to inspect details.

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Percentile 0–100

Dimensional AdvantageOpenAI: o3 Mini 5/6

Preference Elo

OpenAI: o3 Mini

190 pts advantage

Throughput Speed

OpenAI: o3 Mini

50 tok/s faster

Price Efficiency

Llama 3.1 405B

$0.90/1M cheaper

Full Benchmark Score Matrix

—

Elo

High is better

1,370

EloHigh is better

1,560+14%

Code Elo

High is better

1,385

Code EloHigh is better

1,585+14%

LiveBench

High is better

61.2%

LiveBenchHigh is better

72.4%+18%

SWE-bench

High is better

58.4%

SWE-benchHigh is better

78.5%+34%

GPQA

High is better

75.2%

GPQAHigh is better

87.2%+16%

TTFT

Low is better

360 ms

TTFTLow is better

290 ms+24%

Speed

High is better

42 tok/s

SpeedHigh is better

92 tok/s+119%

In $

Low is better

$1.25/1M

In $Low is better

$1.1/1M+14%

Out $

Low is better

+26%$3.5/1M

Out $Low is better

$4.4/1M

Context

High is better

128k

ContextHigh is better

200k+56%

Interactive Simulator

Workload Cost & Savings Calculator

Simulate monthly production API costs based on published $/1M tokens.

Save up to 8% with Llama 3.1 405B

Monthly Volume50M tokens/mo

Quick Presets:

Token Ratio (In vs Out)70% In / 30% Out

RAG / Search (10% out)Coding / Chat (50% out)

Llama 3.1 405B$96.25 / mo

In: $43.75Out: $52.50

OpenAI: o3 Mini$104.50 / mo

In: $38.50Out: $66.00

Estimated Cost Delta

Llama 3.1 405B is estimated to save $8.25/month ($99/year).

Based on 50M tokens (30% gen)

Key Selection Recommendations

1
OpenAI: o3 Mini:Pick OpenAI: o3 Mini when repo-level coding accuracy is the constraint.
2
Llama 3.1 405B:Pick Llama 3.1 405B when you are optimizing output cost.
3
OpenAI: o3 Mini:Pick OpenAI: o3 Mini when time-to-first-token matters more than peak Elo.

Recommended Workload Routing

Repo / coding agentsOpenAI: o3 Mini

Higher SWE-bench (78.5%).

High-volume chatLlama 3.1 405B

Lower output list price ($3.5/1M).

Voice / low-latency UIOpenAI: o3 Mini

Lower TTFT (290 ms).

Long-document RAGOpenAI: o3 Mini

Larger window (200k).

Screenshots / visionOpenAI: o3 Mini

OpenAI: o3 Mini is the side marked multimodal in the catalog.

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	OpenAI: o3 Mini	Higher SWE-bench (78.5%).
High-volume chat	Llama 3.1 405B	Lower output list price ($3.5/1M).
Voice / low-latency UI	OpenAI: o3 Mini	Lower TTFT (290 ms).
Long-document RAG	OpenAI: o3 Mini	Larger window (200k).
Screenshots / vision	OpenAI: o3 Mini	OpenAI: o3 Mini is the side marked multimodal in the catalog.

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LIVE

Llama 3.1 405B

Elo 1,370

LiveBench61.2%

SWE-bench58.4%

Speed42 tok/s

Output cost$3.5/1M

OpenAI

OpenAI: o3 Mini

Elo 1,560

LiveBench72.4%

SWE-bench78.5%

Speed92 tok/s

Output cost$4.4/1M

Frequently Asked Questions

Which is better overall, Llama 3.1 405B or OpenAI: o3 Mini?: OpenAI: o3 Mini has the higher preference Elo in our latest snapshot (1,560). “Better” still depends on coding, price, and latency — see the table.
Which is better at coding, Llama 3.1 405B or OpenAI: o3 Mini?: OpenAI: o3 Mini leads SWE-bench at 78.5% vs 58.4%. SWE-bench is one harness, not your repo.
Which is cheaper to run in production?: Llama 3.1 405B output tokens are $3.5/1M versus $4.4/1M. Input prices and retry rates still move the real bill.
Which is faster, Llama 3.1 405B or OpenAI: o3 Mini?: OpenAI: o3 Mini has the lower time-to-first-token (290 ms vs 360 ms). Tokens/sec is a separate column if you care about long completions.
Which has the larger context window?: OpenAI: o3 Mini accepts 200k tokens versus 128k.
Can I self-host either model?: Llama 3.1 405B is marked open-weights in our catalog. The other side is a closed API. Check the provider license before you ship weights.
Are these scores from CompareLLM’s own evals?: No. V1 aggregates public leaderboards (and optional first-party latency pings). Each cell names its source and date. Read /methodology.
What does preference Elo mean on this page?: Preference Elo is a crowd vote from LMArena / Arena. People see two hidden answers and pick the one they like more. The model that wins more often gets a higher Elo. That means people preferred it — not that it passed a school test. It is not SWE-bench, not accuracy, and not a number we invent. Llama 3.1 405B and OpenAI: o3 Mini Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Similar Head-to-Head Comparisons

All Llama 3.1 405B matchups →|All OpenAI: o3 Mini matchups →

Llama 3.1 405B vs Llama 3.1 70B (next llama)OpenAI: o3 Mini vs OpenAI o1-mini (previous gpt-mini)OpenAI: o3 Mini vs GPT-5 mini (next gpt-mini)Llama 4 Maverick vs OpenAI: o3 Mini GPT-5 vs OpenAI: o3 Mini GPT-4.5 Orion vs OpenAI: o3 Mini

Llama 3.1 405B vs OpenAI: o3 Mini benchmark

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Llama 3.1 405B (1)vsOpenAI: o3 Mini (9)

Llama 3.1 405B: 1W (10%)Overall: OpenAI: o3 MiniOpenAI: o3 Mini: 9W (90%)

← Llama 3.1 405BOpenAI: o3 Mini →

OpenAI: o3 Mini (5/5)

Intelligence & Reasoning

Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy

Preference Elo

1,370vs1,560

Coding Elo

1,385vs1,585

SWE-bench

58.4%vs78.5%

LiveBench

61.2%vs72.4%

GPQA Diamond

75.2%vs87.2%

Llama 3.1 405B: 0WOpenAI: o3 Mini: 5W

OpenAI: o3 Mini (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

42 tok/svs92 tok/s

Time to first token

360 msvs290 ms

Llama 3.1 405B: 0WOpenAI: o3 Mini: 2W

OpenAI: o3 Mini (2/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$3.5/1Mvs$4.4/1M

Input price

$1.25/1Mvs$1.1/1M

Context window

128kvs200k

Llama 3.1 405B: 1WOpenAI: o3 Mini: 2W

Recommended Workload Routing

Repo / coding agentsOpenAI: o3 Mini

Higher SWE-bench (78.5%).

High-volume chatLlama 3.1 405B

Lower output list price ($3.5/1M).

Voice / low-latency UIOpenAI: o3 Mini

Lower TTFT (290 ms).

Long-document RAGOpenAI: o3 Mini

Larger window (200k).

Screenshots / visionOpenAI: o3 Mini

OpenAI: o3 Mini is the side marked multimodal in the catalog.

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	OpenAI: o3 Mini	Higher SWE-bench (78.5%).
High-volume chat	Llama 3.1 405B	Lower output list price ($3.5/1M).
Voice / low-latency UI	OpenAI: o3 Mini	Lower TTFT (290 ms).
Long-document RAG	OpenAI: o3 Mini	Larger window (200k).
Screenshots / vision	OpenAI: o3 Mini	OpenAI: o3 Mini is the side marked multimodal in the catalog.

Frequently Asked Questions

Which is better overall, Llama 3.1 405B or OpenAI: o3 Mini?

OpenAI: o3 Mini has the higher preference Elo in our latest snapshot (1,560). “Better” still depends on coding, price, and latency — see the table.

Which is better at coding, Llama 3.1 405B or OpenAI: o3 Mini?

OpenAI: o3 Mini leads SWE-bench at 78.5% vs 58.4%. SWE-bench is one harness, not your repo.

Which is cheaper to run in production?

Llama 3.1 405B output tokens are $3.5/1M versus $4.4/1M. Input prices and retry rates still move the real bill.

Which is faster, Llama 3.1 405B or OpenAI: o3 Mini?

OpenAI: o3 Mini has the lower time-to-first-token (290 ms vs 360 ms). Tokens/sec is a separate column if you care about long completions.

Which has the larger context window?

OpenAI: o3 Mini accepts 200k tokens versus 128k.

Can I self-host either model?

Llama 3.1 405B is marked open-weights in our catalog. The other side is a closed API. Check the provider license before you ship weights.

Are these scores from CompareLLM’s own evals?

No. V1 aggregates public leaderboards (and optional first-party latency pings). Each cell names its source and date. Read /methodology.

What does preference Elo mean on this page?

Preference Elo is a crowd vote from LMArena / Arena. People see two hidden answers and pick the one they like more. The model that wins more often gets a higher Elo. That means people preferred it — not that it passed a school test. It is not SWE-bench, not accuracy, and not a number we invent. Llama 3.1 405B and OpenAI: o3 Mini Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.