GPT-4.1 vs Llama 3.1 405B

Compare GPT-4.1 and Llama 3.1 405B: pricing, performance, context window, latency, and best use cases. Side-by-side comparison on XALEN.

Updated 2026-05-21 · By Abhishek Raj · Our methodology

All OpenAI models All Meta models What is an LLM API? Python Quickstart What is inference?
Feature GPT-4.1 Llama 3.1 405B
CategoryFrontierOpen Source
Parameters~1.8T405B
Context Window1M128K
Input Price$0.10/1M tokens$0.08/1M tokens
Output Price$0.30/1M tokens$0.14/1M tokens
Latency~500ms~600ms

Choose GPT-4.1 when:

  • ✓ Complex reports
  • ✓ Code generation
  • ✓ Enterprise workflows
Key Strengths:

1M context, Best instruction following, Best coding

Choose Llama 3.1 405B when:

  • ✓ Premium tasks
  • ✓ Research
  • ✓ Fine-tuning base
Key Strengths:

Largest open model, Highest open-source quality

Verdict: GPT-4.1 vs Llama 3.1 405B

For cost efficiency, Llama 3.1 405B wins at $0.08/1M input tokens. For speed, GPT-4.1 is faster at ~500ms. GPT-4.1 excels at Complex reports while Llama 3.1 405B is better for Premium tasks. Both are available on XALEN through a single API — try them in the Playground to see which fits your workload.

Detailed Analysis

Pricing Comparison

GPT-4.1 costs $0.10/1M input tokens and $0.30/1M output tokens. Llama 3.1 405B costs $0.08 input and $0.14 output. Llama 3.1 405B is 1.3x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.

Performance & Context

GPT-4.1 has a 1M context window with ~500ms latency. Llama 3.1 405B offers 128K context at ~600ms. GPT-4.1 has the larger context window.

Best For

GPT-4.1 (Frontier) is optimized for: Complex reports, Code generation, Enterprise workflows. Llama 3.1 405B (Open Source) works best for: Premium tasks, Research, Fine-tuning base.

Try Both on XALEN

Both models are available through XALEN's OpenAI-compatible API. Switch between them by changing the model parameter:

from xalen import XALEN

client = XALEN(api_key="xln_test_YOUR_KEY")

# Use GPT-4.1
response_a = client.chat.completions.create(
    model="gpt-4-1",
    messages=[{"role": "user", "content": "Your question here"}]
)

# Use Llama 3.1 405B
response_b = client.chat.completions.create(
    model="llama-3-1-405b",
    messages=[{"role": "user", "content": "Your question here"}]
)

Start Building with XALEN

200+ AI models. One API. Pay-as-you-go.

Get API Key Try in Playground

Frequently Asked Questions

Which is better, GPT-4.1 or Llama 3.1 405B?

GPT-4.1 (Frontier, ~1.8T) offers 1M context. Llama 3.1 405B (Open Source, 405B) offers Largest open model. Choose GPT-4.1 for Complex reports or Llama 3.1 405B for Premium tasks.

How much does GPT-4.1 cost vs Llama 3.1 405B?

GPT-4.1: $0.10/1M input, $0.30/1M output. Llama 3.1 405B: $0.08/1M input, $0.14/1M output. Both available on XALEN with batch processing at 50% discount.

Can I use both models on XALEN?

Yes. XALEN provides 200+ models through a single OpenAI-compatible API. Switch between GPT-4.1 and Llama 3.1 405B by changing the model parameter. No code changes needed.

Related Comparisons

GPT-4.1 vs GPT-4.1 Mini GPT-4.1 vs GPT-4o GPT-4.1 vs Claude Opus 4 GPT-4.1 vs Claude Sonnet 4 GPT-4.1 vs Claude Opus 4.5 GPT-4.1 vs Claude Sonnet 4.5

Last updated: 2026-05-21. Pricing and specifications may change. Check pricing page for latest rates.