What is the difference between GPT-5.5 and Llama 3.1 405B?

GPT-5.5 is developed by OpenAI while Llama 3.1 405B is developed by Meta AI. GPT-5.5 has a 1.1M token context window vs Llama 3.1 405B's 128K. You can compare their actual outputs across 12 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.5 or Llama 3.1 405B?

It depends on your use case. GPT-5.5 and Llama 3.1 405B each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 12 challenges so you can judge which fits your needs best.

How much does GPT-5.5 cost compared to Llama 3.1 405B?

GPT-5.5 costs $5/M input tokens and Llama 3.1 405B costs $2.7/M input tokens. Llama 3.1 405B is $2.30/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare GPT-5.5 and Llama 3.1 405B on Rival?

This page shows a side-by-side comparison of GPT-5.5 and Llama 3.1 405B across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

What is the difference between GPT-5.5 and Llama 3.1 405B?

GPT-5.5 is developed by OpenAI while Llama 3.1 405B is developed by Meta AI. GPT-5.5 has a 1.1M token context window vs Llama 3.1 405B's 128K. You can compare their actual outputs across 12 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.5 or Llama 3.1 405B?

It depends on your use case. GPT-5.5 and Llama 3.1 405B each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 12 challenges so you can judge which fits your needs best.

How much does GPT-5.5 cost compared to Llama 3.1 405B?

GPT-5.5 costs $5/M input tokens and Llama 3.1 405B costs $2.7/M input tokens. Llama 3.1 405B is $2.30/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare GPT-5.5 and Llama 3.1 405B on Rival?

This page shows a side-by-side comparison of GPT-5.5 and Llama 3.1 405B across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

GPT-5.5 vs Llama 3.1 405B: Which Is Better?

Updated Apr 2026

Our Verdict

GPT-5.5

Llama 3.1 405BRunner-up

No community votes yet. On paper, GPT-5.5 has the edge — newer, bigger context window.

Llama 3.1 405B is 9.7x cheaper per token — worth considering if cost matters.

Too close to call

API pricing

Cost per 1M tokens

GPT-5.5

Input

$5.00

Output

$30.00

Llama 3.1 405B

Input

$2.70

1.9× cheaper

Output

$3.10

9.7× cheaper

Llama 3.1 405B is cheaper on both — 1.9× input, 9.7× output

Writing DNA

Style Comparison

Similarity

46%

GPT-5.5 uses 285.6x more bold

GPT-5.5

Llama 3.1 405B

58%Vocabulary56%

18wSentence Length15w

0.74Hedging0.41

2.9Bold0.0

5.1Lists1.9

0.00Emoji0.03

1.68Headings0.00

0.03Transitions0.16

Based on 26 + 5 text responses

Research

What we learned reading every model

GPT-5.5 and Llama 3.1 405B have opinions about your brand too.Ask 10 models what they tell people about you. Verbatim receipts.Run the mirror

FAQ

Common questions

Keep exploring

More comparisons

Llama 3.1 405B vs MiniMax M3New provider

Llama 3.1 405B vs Claude Opus 4New provider

Llama 3.1 405B vs Gemini 2.5 Pro Preview 06-05New provider

Updated Apr 2026

Our Verdict

GPT-5.5

Llama 3.1 405BRunner-up

No community votes yet. On paper, GPT-5.5 has the edge — newer, bigger context window.

Llama 3.1 405B is 9.7x cheaper per token — worth considering if cost matters.

Too close to call

API pricing

Cost per 1M tokens

GPT-5.5

Input

$5.00

Output

$30.00

Llama 3.1 405B

Input

$2.70

1.9× cheaper

Output

$3.10

9.7× cheaper

Llama 3.1 405B is cheaper on both — 1.9× input, 9.7× output

Writing DNA

Style Comparison

Similarity

46%

GPT-5.5 uses 285.6x more bold

GPT-5.5

Llama 3.1 405B

58%Vocabulary56%

18wSentence Length15w

0.74Hedging0.41

2.9Bold0.0

5.1Lists1.9

0.00Emoji0.03

1.68Headings0.00

0.03Transitions0.16

Based on 26 + 5 text responses

Research

What we learned reading every model

GPT-5.5 and Llama 3.1 405B have opinions about your brand too.Ask 10 models what they tell people about you. Verbatim receipts.Run the mirror

FAQ

Common questions

Keep exploring

More comparisons

Llama 3.1 405B vs MiniMax M3New provider

Llama 3.1 405B vs Claude Opus 4New provider

Llama 3.1 405B vs Gemini 2.5 Pro Preview 06-05New provider