Claude Opus 4.5 vs Llama 3.1 405B
Compare Claude Opus 4.5 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
| Feature | Claude Opus 4.5 | Llama 3.1 405B |
|---|---|---|
| Category | Frontier | Open Source |
| Parameters | ~2.5T | 405B |
| Context Window | 200K | 128K |
| Input Price | $0.15/1M tokens | $0.08/1M tokens |
| Output Price | $0.75/1M tokens | $0.14/1M tokens |
| Latency | ~900ms | ~600ms |
Choose Claude Opus 4.5 when:
- ✓ Creative writing
- ✓ Complex analysis
- ✓ Research
Superior creativity, Nuanced reasoning, Complex analysis
Choose Llama 3.1 405B when:
- ✓ Premium tasks
- ✓ Research
- ✓ Fine-tuning base
Largest open model, Highest open-source quality
Verdict: Claude Opus 4.5 vs Llama 3.1 405B
For cost efficiency, Llama 3.1 405B wins at $0.08/1M input tokens. For speed, Llama 3.1 405B is faster at ~600ms. Claude Opus 4.5 excels at Creative writing 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
Claude Opus 4.5 costs $0.15/1M input tokens and $0.75/1M output tokens. Llama 3.1 405B costs $0.08 input and $0.14 output. Llama 3.1 405B is 1.9x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.
Performance & Context
Claude Opus 4.5 has a 200K context window with ~900ms latency. Llama 3.1 405B offers 128K context at ~600ms. Claude Opus 4.5 has the larger context window.
Best For
Claude Opus 4.5 (Frontier) is optimized for: Creative writing, Complex analysis, Research. 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 Claude Opus 4.5
response_a = client.chat.completions.create(
model="claude-opus-4-5",
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"}]
)Frequently Asked Questions
Which is better, Claude Opus 4.5 or Llama 3.1 405B?
Claude Opus 4.5 (Frontier, ~2.5T) offers Superior creativity. Llama 3.1 405B (Open Source, 405B) offers Largest open model. Choose Claude Opus 4.5 for Creative writing or Llama 3.1 405B for Premium tasks.
How much does Claude Opus 4.5 cost vs Llama 3.1 405B?
Claude Opus 4.5: $0.15/1M input, $0.75/1M 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 Claude Opus 4.5 and Llama 3.1 405B by changing the model parameter. No code changes needed.
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Last updated: 2026-05-21. Pricing and specifications may change. Check pricing page for latest rates.