Buying guide
The 2026 buying guide: which Mac for local AI?
Rule one: confirm memory fit before comparing speed. Unified memory on Apple Silicon can't be upgraded later, and it decides which models you can load at all. Rule two: among machines with enough memory, bandwidth is one important influence on token-generation speed. Runtime and model architecture matter too.
Step 1: Decide the biggest model you'll run
Use the calculator. As rough guidance from the weight formula alone (4-bit MLX, ≈4.5 bits/weight): 8B ≈ 4.5GB, 14B ≈ 7.9GB, 32B ≈ 18GB, 70B ≈ 39GB, plus KV cache and headroom for macOS.
Step 2: Match to a memory tier
| Memory | Possible starting point; verify the exact model |
|---|---|
| 16–24GB | Smaller 4-bit models; 14B and longer contexts need individual checks |
| 32–48GB | Some medium-sized quantized models; include cache and runtime memory |
| 64–128GB | Some 70B-class quantized models; long contexts can require a larger tier |
| 256GB | Larger total allocations, subject to architecture and runtime support |
| 512GB | A capacity option, not a guarantee that any particular model runs well |
These are estimation ranges, not tested compatibility ratings. Work through the arithmetic in our memory guide; always check a specific model's file size.
Step 3: Pick the machine
- Mac Studio M5 Max — from $2,499, 36GB base, up to 128GB, up to 614GB/s.
- Mac Studio M5 Ultra — from $5,499, 96GB base, 256GB, and 512GB listed by Apple; check current configuration availability; up to 1.2TB/s.
Prices above are the US starting prices announced by Apple on August 25, 2026, before tax and upgrades; they are not current quotations. Specifications were checked October 21, 2026. Check the Apple US Store for current pricing and delivery.
Before spending anything
Check whether a smaller model and shorter context on your existing Mac meet the need. If an upgrade remains useful, compare the complete configuration price, return policy, and Apple Certified Refurbished options. A theoretical fit alone is not a reason to buy a machine.
Don't forget storage
Model files are large — a 70B 4-bit model is roughly 40GB on disk — and you'll keep several. Budget internal SSD or a fast Thunderbolt 5 drive.
Sources
- Apple Newsroom — Mac Studio M5 Max / M5 Ultra pricing and availability
- Apple — Mac Studio Technical Specifications
- Apple Certified Refurbished Mac
Figures are taken from the sources above. Where we estimate (e.g. memory math) we show the formula. We do not publish benchmark numbers we have not sourced.