How to Run Llama 3 on Mac (Apple Silicon & Intel)

Run Llama 3 on macOS in 15 Minutes

Published on April 5, 2025 • 13 min read

Apple Silicon turned MacBooks into capable local AI rigs. With the right quantized weights you can run Llama 3 entirely offline—no cloud, no subscriptions, complete privacy. This walkthrough gets you from clean macOS install to a tuned, Metal-accelerated Llama 3 chat in under 15 minutes.

Table of Contents

1. Prerequisites
2. Step 1 – Install Command Line Tools & Homebrew
3. Step 2 – Install Ollama
4. Step 3 – Download Llama 3 Models
5. Step 4 – Run & Optimize Llama 3
6. Troubleshooting
7. FAQ
8. Next Steps

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Prerequisites {#prerequisites}

• macOS 13.5 Ventura or newer (Sonoma recommended)
• 12GB+ unified memory for Llama 3 8B, 24GB for 70B
• 20GB of free SSD space
• Command Line Tools + Homebrew (installed in Step 1)

Step 1 – Install Command Line Tools & Homebrew {#step-1}

1. Open Terminal (Spotlight → Terminal).
2. Install Command Line Tools:

xcode-select --install

1. Install Homebrew:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

Step 2 – Install Ollama {#step-2}

1. Download the latest Ollama.dmg from ollama.com.
2. Drag Ollama.app into Applications.
3. Launch Ollama and approve the security prompt (System Settings → Privacy & Security → Allow).
4. Start the Ollama service:

launchctl load /Library/LaunchDaemons/com.ollama.ollama.plist

Step 3 – Download Llama 3 Models {#step-3}

Step 4 – Run & Optimize Llama 3 {#step-4}

Run your first chat:

ollama run llama3.1:8b

Enable Metal acceleration and larger context windows by editing ~/.ollama/config.yaml:

vm:
  memory: 12g
  compute: [metal, cpu]
llm:
  context_length: 4096
  num_ctx: 4096

Restart Ollama: ollama run --set default.

Troubleshooting {#troubleshooting}

• Model fails to load (out of memory): Try the Q4_K_S build (ollama pull llama3.1:8b-q4_k_s).
• Fans ramp up immediately: Set compute: [metal] and cap power with pmset -a reducespeed 1 during long sessions.
• Slow tokens on Intel: Use --num-parallel 2 and lower context to 2048.
• Want automation? Integrate with Automator Quick Actions to send highlighted text directly to Llama 3.

FAQ {#faq}

• Can my M1 MacBook Air run Llama 3? Yes—stick with Q4 builds and keep the device plugged in.
• Do I need a GPU? Apple Silicon GPUs are built in; Intel users can still run CPU-only with lower speed.
• How do I update to the latest weights? Pull the new tag with ollama pull llama3.2 and remove older versions.

Next Steps {#next-steps}

• Add vision or code assistants from the models directory.
• Compare GPU options if you dual-boot Windows by visiting the hardware guide.
• Need offline workflows? Read Run AI Offline for privacy hardening.
• Building workflows? Use our Choose the Right AI Model framework to match tasks to models.