GPT-4.5 vs Llama 3.1 405B Instruct
GPT-4.5 and Llama 3.1 405B Instruct are closely matched at 20.5 and 15.2 on the LLM Stats Score. Llama 3.1 405B Instruct is 105.3x cheaper per token.
OpenAI · Meta · Updated for 2026
Which is better?
GPT-4.5 and Llama 3.1 405B Instruct are closely matched on the overall LLM Stats Score at 20.5 and 15.2.
In the 5 individual benchmarks reported for both models, GPT-4.5 wins 3; this is a narrower head-to-head signal than the composite indexes.
On price, Llama 3.1 405B Instruct is roughly 105.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GPT-4.5
- your work emphasizes reasoning — it leads those capability indexes
- you value its reported benchmark strengths — it wins 3 of 5 exact shared results
- you want the most recent training data — it shipped Feb 2025
Choose Llama 3.1 405B Instruct
- cost matters — it's about 105.3x cheaper per token
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
26 reported for GPT-4.5 · 18 for Llama 3.1 405B Instruct
GPT-4.5 outperforms in 3 benchmarks (GPQA, GSM8k, MMLU), while Llama 3.1 405B Instruct is better at 2 benchmarks (HumanEval, IFEval).
GPT-4.5 has a slight edge in benchmark performance.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-4.5 ($75.00/1M tokens) is 84.3x more expensive than Llama 3.1 405B Instruct ($0.89/1M tokens).
For output processing, GPT-4.5 ($150.00/1M tokens) is 168.5x more expensive than Llama 3.1 405B Instruct ($0.89/1M tokens).
In conclusion, GPT-4.5 is more expensive than Llama 3.1 405B Instruct.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Both models have the same input context window of 128,000 tokens. Llama 3.1 405B Instruct can generate longer responses up to 128,000 tokens, while GPT-4.5 is limited to 4,096 tokens.
Input capabilities
Documented input modalities across available providers
GPT-4.5 supports multimodal inputs, whereas Llama 3.1 405B Instruct does not.
GPT-4.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.
GPT-4.5
Llama 3.1 405B Instruct
License
Usage and distribution terms
GPT-4.5 is licensed under a proprietary license, while Llama 3.1 405B Instruct uses Llama 3.1 Community License.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
Llama 3.1 Community License
Open weights
Release Timeline
When each model was launched
GPT-4.5 was released on 2025-02-27, while Llama 3.1 405B Instruct was released on 2024-07-23.
GPT-4.5 is 7 months newer than Llama 3.1 405B Instruct.
Feb 27, 2025
1.5 years ago
7mo newerJul 23, 2024
2.1 years ago
Knowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
GPT-4.5 is available from OpenAI. Llama 3.1 405B Instruct is available from Lambda, DeepInfra, Fireworks, Bedrock, Together, Hyperbolic, Google, Replicate.
GPT-4.5
Llama 3.1 405B Instruct
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-4.5 and Llama 3.1 405B Instruct side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-4.5 vs Llama 3.1 405B Instruct.