Memory Bandwidth Determines Multi-Tasking Ceiling

The M4 Max's 546GB/s unified memory bandwidth—4× the base M4's 120GB/s—creates qualitative differences beyond raw speed.

🚀 Scenarios Where Bandwidth Matters DramaticallyRunning 5+ heavy applications simultaneously (Xcode, Android Studio, Docker, multiple browsers, Figma)
Working with large datasets in Jupyter notebooks (10GB+ DataFrames)
Real-time video processing in development tools
Training local LLMs with 70B+ parameters

Developers report the M4 Max maintains responsiveness when juggling:

Xcode with 3 simulator instances
VS Code with 50+ TypeScript files open
Docker running 12 microservices
Chrome with 40+ tabs
Figma with multiple design files
Slack, Spotify, Mail running simultaneously

Switching between these contexts shows zero perceptible lag. The M4 Pro (273GB/s) stutters occasionally; the base M4 (120GB/s) swaps to disk under this load, destroying performance.

🤖 For ML Developers

The M4 Max loads Llama 3 70B models entirely in memory with 128GB RAM, running inference at ~25 tokens/second—respectable for local development and testing before deploying to cloud infrastructure.