SSyncDev

AI model comparison

Llama 3.1 405B vs Gpt 5.3 Chat

Compare recorded price, context, output limits, speed, latency, capabilities, and input/output support. Every missing value stays visible, and unsourced benchmarks are excluded.

This Llama 3.1 405B vs Gpt 5.3 Chat comparison is designed for teams choosing between two production model records, not for declaring a universal winner. Llama 3.1 405B by Meta currently records 128K context, 4.1K maximum output, $3.50 input per 1M tokens, $3.50 output per 1M tokens, 30 t/s recorded output speed, 0.70s recorded time to first token. Gpt 5.3 Chat by Openai via Requesty records 128K context, 16.4K maximum output, $1.75 input per 1M tokens, $14.00 output per 1M tokens. The tables below separate documented capabilities, commercial limits, directory measurements, and source-linked benchmark evidence so you can see where the data is complete and where independent testing is still required.

Side-by-sideSpecs and pricing, compared

Meta

Llama 3.1 405B

Meta's largest open-weights model, competitive with frontier closed models.

Context
128K
Max output
4.1K
Input / 1M
$3.50
Output / 1M
$3.50
Output speed
30 t/s

Accepts

  • Text input

Produces

  • Text output
Full model profileVendor docs ↗
VS

Openai via Requesty

Gpt 5.3 Chat

GPT-5.3 Chat is an update to ChatGPT's most-used model that makes everyday conversations smoother, more useful, and more directly helpful. It delivers more accurate answers with better contextualization and significantly reduces unnecessary refusals, caveats, and overly cautious phrasing that can interrupt conversational flow.

Context
128K
Max output
16.4K
Input / 1M
$1.75
Output / 1M
$14.00
Output speed
—

Accepts

  • Text input
  • Image input

Produces

  • Text output
Full model profileVendor docs ↗

At a glance

Decision snapshot

This is a directional summary of the values recorded in this directory—not a universal quality verdict. Test the finalists on your own prompts before committing.

Where Llama 3.1 405B leads in recorded data

  • Output price: $3.50

Where Gpt 5.3 Chat leads in recorded data

  • Maximum output: 16.4K
  • Input price: $1.75

Context capacity

Higher listed limit

Llama 3.1 405B:128K

Gpt 5.3 Chat:128K

Same recorded value

Maximum output

Higher listed limit

Llama 3.1 405B:4.1K

Gpt 5.3 Chat:16.4K

Gpt 5.3 Chat

Input price

Lower recorded price

Llama 3.1 405B:$3.50

Gpt 5.3 Chat:$1.75

Gpt 5.3 Chat

Output price

Lower recorded price

Llama 3.1 405B:$3.50

Gpt 5.3 Chat:$14.00

Llama 3.1 405B

Output speed

Higher recorded throughput

Llama 3.1 405B:30 t/s

Gpt 5.3 Chat:—

No complete comparison

Time to first token

Lower recorded latency

Llama 3.1 405B:0.70s

Gpt 5.3 Chat:—

No complete comparison

Intelligence Index

Higher directory index

Llama 3.1 405B:74.0

Gpt 5.3 Chat:—

No complete comparison

Evidence

Verified shared benchmarks

A score appears only when both records include a verified source. It is not treated as a universal ranking.

These two models haven't been measured on the same benchmark yet, so there's nothing meaningful to chart. Comparing scores from different tests would tell you more about the tests than the models — the specs and pricing above are the better guide here.

Specifications

Pricing, limits and capabilities

SpecificationLlama 3.1 405BGpt 5.3 Chat
ProviderMetaOpenai via Requesty
Model familyLlama 3.1—
Accepted inputstexttext, image
Produced outputstexttext
Context window128K128K
Max output4.1K16.4KRecorded lead
Intelligence Index74.0—
Input price / 1M$3.50$1.75Recorded lead
Output price / 1M$3.50Recorded lead$14.00
Output speed30 t/s—
Time to first token0.70s—
Reasoning modeNot documentedDocumented
Tool callingDocumentedDocumented
Image inputNot documentedDocumented
Audio inputNot documentedNot documented
Structured outputDocumentedDocumented
LicenseOpen weightsNot documented
ReleasedJul 23, 2024Mar 20, 2026

Workload guidance

Which model should you choose?

Llama 3.1 405B currently leads on lower recorded output price. Gpt 5.3 Chat currently leads on larger maximum output, lower recorded input price. Choose according to the constraints that matter to your workload, then run the same representative prompts against both models before making a production commitment. Neither the larger number nor the lower price is automatically the better choice: prompt quality, tool reliability, modality support, rate limits, data policy, and provider implementation can change the result. Use this page to build a shortlist, confirm current terms in the linked sources, and validate quality, latency, and cost with your own traffic.

Provenance

Sources and data limits

Prices and hosted performance can change. SyncDev records source references and clearly separates documented specifications from measured values; confirm commercial terms with the provider before deployment.

Questions people ask

It compares recorded context and output limits, token prices, output speed, time to first token, Intelligence Index, modality support, tool and structured-output capabilities, release information, and only source-linked benchmarks verified on both records. Missing information is labeled rather than inferred.

Compare a different pair

Choose any two approved model records and review them with the same evidence rules.

Open model comparison