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Llama 5 vs Llama 4: What Changed in Meta's New Model

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Llama 5 vs Llama 4: What Actually Changed

Meta released Llama 5 on April 8, 2026, replacing Llama 4 as the flagship open-weight model. Here’s every meaningful difference.

Last verified: April 10, 2026

Quick Comparison

FeatureLlama 4Llama 5
Released2025April 8, 2026
Flagship size405B dense600B+ MoE
ArchitectureDenseMixture-of-Experts
Context window256K tokens5M tokens
Training computeH100 cluster500K+ Blackwell B200
ModalitiesText, imageText, image, video, audio
Native agentsPartialFull
Recursive self-improvement❌ No✅ Yes
SWE-bench Verified~62%~74%
MMLU-Pro~80%~87%
LicenseLlama Community LicenseLlama Community License (updated)

Architecture Changes

Llama 4: Dense

Llama 4 used a dense transformer — every parameter activates for every token. 405B parameters meant 405B active every forward pass. Simple to serve, but expensive at scale.

Llama 5: Mixture-of-Experts (MoE)

Llama 5’s flagship has 600B+ total parameters, but only a fraction (likely ~40-80B, similar to DeepSeek V4’s design) activate per token. This makes inference 3-5x cheaper while allowing a much larger total parameter count.

Why it matters: You get more capability for the same inference cost, but serving MoE is more complex (needs expert routing, load balancing).

Context Window: 256K → 5M

Llama 4 capped at 256K tokens (enough for long documents, not for whole codebases). Llama 5 jumps to 5 million tokens — the longest of any frontier model in April 2026.

Practical implications:

  • Ingest an entire medium-sized repository in one prompt
  • Process book-length documents without chunking
  • Long-horizon agent trajectories without memory compression

Recursive Self-Improvement (New)

Llama 5 introduces the ability to refine its own internal logic and generate high-quality synthetic training data. Meta describes this as moving toward “System 2 thinking” — slow, deliberate reasoning.

Llama 4 had no equivalent. This is the biggest architectural innovation of Llama 5 and the main reason Meta claims it matches closed frontier models on hard reasoning benchmarks.

Native Agentic Training

Llama 4 could be fine-tuned for agent workflows, but agentic behavior wasn’t baked in. Llama 5 is trained from the start on tool use, planning, and multi-step execution. You get:

  • Better out-of-the-box function calling
  • Stronger multi-step planning without prompt scaffolding
  • Improved resistance to agent failure modes (loops, hallucinated tool calls)

Multimodal: Text+Image → Text+Image+Video+Audio

Llama 4 handled text and images. Llama 5 adds native video and audio input, matching GPT-5.4 and Gemini 3.1 Pro.

Benchmark Deltas

BenchmarkLlama 4Llama 5Delta
MMLU-Pro~80%~87%+7 pts
SWE-bench Verified~62%~74%+12 pts
AIME 2025~70%~88%+18 pts
GPQA Diamond~72%~84%+12 pts
HumanEval~89%~94%+5 pts
LiveCodeBench~52%~68%+16 pts

These are the largest generation-over-generation gains in Llama history — bigger than the Llama 3 → Llama 4 jump.

License Changes

Both use the Llama Community License, but Llama 5 updates a few terms:

  • Attribution: Still required (“Built with Llama”)
  • MAU cap: Still 700M for the separate-agreement trigger
  • Training other models: Llama 5 explicitly allows using outputs to train other models (Llama 4 was ambiguous)
  • Multimodal outputs: Covered under the same terms

Migration Notes

  • Tokenizer: Updated for Llama 5 — don’t mix Llama 4 and Llama 5 tokenizers
  • Chat template: Minor formatting changes; update your prompt wrappers
  • Fine-tunes: Llama 4 LoRAs and full fine-tunes do NOT transfer to Llama 5
  • Tool use format: Llama 5 uses a cleaner JSON-based tool schema
  • API clients: Hosted provider APIs (Together, Fireworks, Groq) accept a drop-in model name change

Should You Upgrade?

Upgrade if:

  • You have hardware to run Llama 5 (even the 70B distilled variant)
  • You need longer context or better reasoning
  • You’re building agents
  • You want multimodal

⚠️ Stay on Llama 4 if:

  • Your hardware can’t handle Llama 5
  • You have production fine-tunes you can’t easily retrain
  • Your workload is simple enough that Llama 4 is “good enough”

For most teams, upgrade. The benchmark gains alone justify the migration effort.

Last verified: April 10, 2026