Claude Mythos Preview vs IBM Granite 4.0

Which one should you pick? Here's the full breakdown.

Claude Mythos Preview

C
6.5/10

Anthropic's most capable model -- a gated research preview via Project Glasswing, cybersecurity-specialized. 73% success on expert CTF tasks, 32-step autonomous network attacks. Not generally available.

Our Pick

IBM Granite 4.0

A
8.2/10

IBM's enterprise-focused open-weight family -- Granite 4.0 hybrid Mamba-2 + transformer architecture (70-80% memory reduction vs pure transformer), 3B to 32B sizes, Apache 2.0. First open model family to secure ISO 42001 certification. Nano 350M runs on CPU with 8-16GB RAM. 3B Vision variant landed 2026-04-01

CategoryClaude Mythos PreviewIBM Granite 4.0
Ease of Use2.07.0
Output Quality10.08.0
Value5.09.5
Features9.08.5
Overall6.58.2

Pricing Comparison

FeatureClaude Mythos PreviewIBM Granite 4.0
Free TierNoYes
Starting PriceInvite only$0

Which Should You Pick?

Pick Claude Mythos Preview if...

  • Higher output quality (10 vs 8)

Partner organizations in Project Glasswing doing cybersecurity research, defensive red-teaming, threat intelligence, or large-scale vulnerability triage. If your use case is legitimate cybersecurity and you have enterprise Anthropic contact, ask about Glasswing admission.

Visit Claude Mythos Preview

Pick IBM Granite 4.0 if...

  • Easier to use (7 vs 2)
  • Better value for money (9.5/10)
  • Has a free tier

Regulated-industry enterprises (healthcare, finance, government) who need Apache 2.0 open-weight models with ISO 42001 certification. Also ideal for edge deployments where Granite Nano (350M / 1.5B) is one of the few open models that runs realistically on CPU. And for any Mamba-hybrid research or low-memory production use where the 70-80% memory reduction actually changes the economics.

Visit IBM Granite 4.0

Our Verdict

IBM Granite 4.0 is the clear winner here with 8.2/10 vs 6.5/10. Claude Mythos Preview isn't bad, but IBM Granite 4.0 outperforms it across the board. Pick Claude Mythos Preview only if partner organizations in project glasswing doing cybersecurity research, defensive red-teaming, threat intelligence, or large-scale vulnerability triage.