Pairwise benchmark snapshot · Aug 16, 2026

GPT-5.6 Terra vs Llama 3.1 405B benchmark

Name: GPT-5.6 Terra vs Llama 3.1 405B AI benchmark comparison
Creator: CompareLLM
License: https://creativecommons.org/licenses/by/4.0/

This page compares GPT-5.6 Terra (OpenAI) and Llama 3.1 405B (Meta) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, GPT-5.6 Terra is ahead by 178 points (1,548 vs 1,370; seed-bootstrap (Aug 16, 2026)). On SWE-bench coding, GPT-5.6 Terra resolves 70.4% versus 58.4% (seed-bootstrap (Aug 16, 2026)). GPT-5.6 Terra streams faster (128 tok/s) while Llama 3.1 405B is the cheaper output token ($3.5/1M). GPT-5.6 Terra has the larger context window (1.1M 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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OpenAI

GPT-5.6 Terra

OpenAI 5.6 mid tier. Official API $2/$12 per 1M after the Jul 30 2026 price cut.

Elo 1,548$6/1M out

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Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

GPT-5.6 Terra (9)vsLlama 3.1 405B (1)

GPT-5.6 Terra: 9W (90%)Overall: GPT-5.6 TerraLlama 3.1 405B: 1W (10%)

← GPT-5.6 TerraLlama 3.1 405B →

GPT-5.6 Terra (5/5)

Intelligence & Reasoning

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

Preference Elo

1,548vs1,370

Coding Elo

1,542vs1,385

SWE-bench

70.4%vs58.4%

LiveBench

69.1%vs61.2%

GPQA Diamond

82%vs75.2%

GPT-5.6 Terra: 5WLlama 3.1 405B: 0W

GPT-5.6 Terra (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

128 tok/svs42 tok/s

Time to first token

160 msvs360 ms

GPT-5.6 Terra: 2WLlama 3.1 405B: 0W

GPT-5.6 Terra (2/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$6/1Mvs$3.5/1M

Input price

$1/1Mvs$1.25/1M

Context window

1.1Mvs128k

GPT-5.6 Terra: 2WLlama 3.1 405B: 1W

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.

Tap any node to inspect

Percentile 0–100

Dimensional AdvantageGPT-5.6 Terra 5/6

Preference Elo

GPT-5.6 Terra

178 pts advantage

Throughput Speed

GPT-5.6 Terra

86 tok/s faster

Price Efficiency

Llama 3.1 405B

$2.50/1M cheaper

Full Benchmark Score Matrix

—

Elo

High is better

+13%1,548

EloHigh is better

1,370

Code Elo

High is better

+11%1,542

Code EloHigh is better

1,385

LiveBench

High is better

+13%69.1%

LiveBenchHigh is better

61.2%

SWE-bench

High is better

+21%70.4%

SWE-benchHigh is better

58.4%

GPQA

High is better

+9%82%

GPQAHigh is better

75.2%

TTFT

Low is better

+125%160 ms

TTFTLow is better

360 ms

Speed

High is better

+205%128 tok/s

SpeedHigh is better

42 tok/s

In $

Low is better

+25%$1/1M

In $Low is better

$1.25/1M

Out $

Low is better

$6/1M

Out $Low is better

$3.5/1M+71%

Context

High is better

+720%1.1M

ContextHigh is better

128k

Interactive Simulator

Workload Cost & Savings Calculator

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

Save up to 23% 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)

GPT-5.6 Terra$125.00 / mo

In: $35.00Out: $90.00

Llama 3.1 405B$96.25 / mo

In: $43.75Out: $52.50

Estimated Cost Delta

Llama 3.1 405B is estimated to save $28.75/month ($345/year).

Based on 50M tokens (30% gen)

Key Selection Recommendations

1
GPT-5.6 Terra:Pick GPT-5.6 Terra 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
GPT-5.6 Terra:Pick GPT-5.6 Terra when time-to-first-token matters more than peak Elo.

Recommended Workload Routing

Repo / coding agentsGPT-5.6 Terra

Higher SWE-bench (70.4%).

High-volume chatLlama 3.1 405B

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

Voice / low-latency UIGPT-5.6 Terra

Lower TTFT (160 ms).

Long-document RAGGPT-5.6 Terra

Larger window (1.1M).

Screenshots / visionGPT-5.6 Terra

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.

Related Editorial Dispatches & Benchmark Notes

View all news

priceJul 30, 2026

GPT-5.6 Terra after the Jul 30 cut: $2/$12 mid-tier

Terra is OpenAI’s Sonnet-class invoice. Use it when Sol is too expensive and Luna is too small.

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LIVE

OpenAI

GPT-5.6 Terra

Elo 1,548

LiveBench69.1%

SWE-bench70.4%

Speed128 tok/s

Output cost$6/1M

Llama 3.1 405B

Elo 1,370

LiveBench61.2%

SWE-bench58.4%

Speed42 tok/s

Output cost$3.5/1M

Frequently Asked Questions

Which is better overall, GPT-5.6 Terra or Llama 3.1 405B?: GPT-5.6 Terra has the higher preference Elo in our latest snapshot (1,548). “Better” still depends on coding, price, and latency — see the table.
Which is better at coding, GPT-5.6 Terra or Llama 3.1 405B?: GPT-5.6 Terra leads SWE-bench at 70.4% 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 $6/1M. Input prices and retry rates still move the real bill.
Which is faster, GPT-5.6 Terra or Llama 3.1 405B?: GPT-5.6 Terra has the lower time-to-first-token (160 ms vs 360 ms). Tokens/sec is a separate column if you care about long completions.
Which has the larger context window?: GPT-5.6 Terra accepts 1.1M 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. GPT-5.6 Terra and Llama 3.1 405B Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Similar Head-to-Head Comparisons

All GPT-5.6 Terra matchups →|All Llama 3.1 405B matchups →

Llama 3.1 405B vs Llama 3.1 70B (next llama)GPT-4.5 Orion vs GPT-5.6 Terra GPT-5 vs GPT-5.6 Terra GPT-5.6 Sol vs GPT-5.6 Terra Llama 4 Maverick vs GPT-5.6 Terra OpenAI: o3 Mini vs GPT-5.6 Terra

GPT-5.6 Terra vs Llama 3.1 405B benchmark

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

GPT-5.6 Terra (9)vsLlama 3.1 405B (1)

GPT-5.6 Terra: 9W (90%)Overall: GPT-5.6 TerraLlama 3.1 405B: 1W (10%)

← GPT-5.6 TerraLlama 3.1 405B →

GPT-5.6 Terra (5/5)

Intelligence & Reasoning

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

Preference Elo

1,548vs1,370

Coding Elo

1,542vs1,385

SWE-bench

70.4%vs58.4%

LiveBench

69.1%vs61.2%

GPQA Diamond

82%vs75.2%

GPT-5.6 Terra: 5WLlama 3.1 405B: 0W

GPT-5.6 Terra (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

128 tok/svs42 tok/s

Time to first token

160 msvs360 ms

GPT-5.6 Terra: 2WLlama 3.1 405B: 0W

GPT-5.6 Terra (2/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$6/1Mvs$3.5/1M

Input price

$1/1Mvs$1.25/1M

Context window

1.1Mvs128k

GPT-5.6 Terra: 2WLlama 3.1 405B: 1W

Recommended Workload Routing

Repo / coding agentsGPT-5.6 Terra

Higher SWE-bench (70.4%).

High-volume chatLlama 3.1 405B

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

Voice / low-latency UIGPT-5.6 Terra

Lower TTFT (160 ms).

Long-document RAGGPT-5.6 Terra

Larger window (1.1M).

Screenshots / visionGPT-5.6 Terra

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.

Frequently Asked Questions

Which is better overall, GPT-5.6 Terra or Llama 3.1 405B?

GPT-5.6 Terra has the higher preference Elo in our latest snapshot (1,548). “Better” still depends on coding, price, and latency — see the table.

Which is better at coding, GPT-5.6 Terra or Llama 3.1 405B?

GPT-5.6 Terra leads SWE-bench at 70.4% 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 $6/1M. Input prices and retry rates still move the real bill.

Which is faster, GPT-5.6 Terra or Llama 3.1 405B?

GPT-5.6 Terra has the lower time-to-first-token (160 ms vs 360 ms). Tokens/sec is a separate column if you care about long completions.

Which has the larger context window?

GPT-5.6 Terra accepts 1.1M 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. GPT-5.6 Terra and Llama 3.1 405B Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

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Interactive Comparison Diagram

Tug-of-War Matchup Matrix

Intelligence & Reasoning

Speed & Latency

Pricing & Capacity

Multi-Dimensional Capability Radar

GPT-5.6 Terra

GPT-5.6 Terra

Llama 3.1 405B

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

GPT-5.6 Terra after the Jul 30 cut: $2/$12 mid-tier

Cast Your Matchup Vote

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CompareLLM Matrix

GPT-5.6 Terra

Llama 3.1 405B

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons

Swap or Add Any Model to this Matchup

Interactive Comparison Diagram

Tug-of-War Matchup Matrix

Intelligence & Reasoning

Speed & Latency

Pricing & Capacity

Multi-Dimensional Capability Radar

GPT-5.6 Terra

GPT-5.6 Terra

Llama 3.1 405B

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

GPT-5.6 Terra after the Jul 30 cut: $2/$12 mid-tier

Cast Your Matchup Vote

Community Discussions (0)

Share card

CompareLLM Matrix

GPT-5.6 Terra

Llama 3.1 405B

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons