Hardware

Mac Studio M5 Max vs. M5 Ultra for local AI — and the 512GB question

By Claudio A. G. M. Filho · Updated October 21, 2026

Apple announced the new Mac Studio on August 25, 2026, with two chips: M5 Max and the new M5 Ultra. Orders opened that day; Apple announced availability beginning September 22. Apple lists a 512GB unified-memory configuration for Mac Studio with M5 Ultra. Check Apple’s current store for configuration pricing and delivery estimates; this guide does not establish current stock or a shipping date.

The two chips, by the numbers Apple published

Per Apple's spec page, 48GB and higher on M5 Max require the 40-core GPU, and 256GB/512GB on M5 Ultra require the 36-core CPU / 80-core GPU chip. Check the current store for the complete configuration price and delivery estimate.

Why memory matters more than cores

For local LLMs the first question is not speed, it's fit. A model's weights must live in memory, plus a working buffer (the KV cache) that grows with context length. On Apple Silicon the CPU and GPU share one pool, so total installed memory is not the same as the memory available to a model. macOS, other applications, and the runtime also need space; Metal exposes a device-specific recommended working set (see our unified memory guide).

The second question is bandwidth. For many single-stream dense-model workloads, reading model weights is a major cost. Bandwidth is therefore relevant, but it is not a tokens-per-second prediction: architecture, quantization, context, runtime, and concurrent work also matter.

Published claims versus measured results

Apple publishes AI performance comparisons in its announcement, with specific test configurations and footnotes. MacModelFit has not reproduced them. Prompt processing, generation speed, and end-to-end response time are different measurements; none can be inferred from memory capacity alone.

Choose from the workload, not the largest number

• Start with your existing Mac. Try a supported smaller model before deciding an upgrade is necessary.
• Estimate the whole allocation. Include weights, context cache, and runtime headroom with the calculator.
• Validate a specific setup. A capacity estimate does not verify model support, acceptable response speed, or the ability to fine-tune.
• Check availability and the complete price. The largest memory tier is not automatically the right purchase.

Specifications checked against Apple's official pages on October 20, 2026. MacModelFit is independent and does not claim Apple endorsement.