Memory at each precision
| Version | Weights | With context | Smallest Mac |
|---|---|---|---|
| 8-bit | 31.9 GB | 34.5 GB | 48 GB |
| 6-bit | 24.4 GB | 26.4 GB | 36 GB |
| 4-bit | 16.9 GB | 18.4 GB | 32 GB |
| 3-bit lower quality | 13.1 GB | 14.6 GB | 24 GB |
| 2-bit lower quality | 9.4 GB | 10.9 GB | 16 GB |
On every Apple chip
The smallest memory size of each chip that runs Granite 4.2 30B, the best version that fits it, and the writing speed you can expect.
| Chip | Needs | Version | Tokens/s |
|---|---|---|---|
| M6 | 32 GB | 4-bit Slow | 5–8 |
| M5 Ultra | 96 GB | 8-bit Runs well | 17–30 |
| M5 Max | 36 GB | 4-bit Runs well | 12–22 |
| M5 Pro | 48 GB | 8-bit Slow | 4–8 |
| M5 | 32 GB | 4-bit Slow | 4–7 |
| M4 Max | 36 GB | 4-bit Runs well | 11–19 |
| M4 Pro | 48 GB | 8-bit Slow | 4–7 |
| M4 | 32 GB | 4-bit Slow | 3–6 |
| M3 Ultra | 96 GB | 8-bit Runs well | 12–21 |
| M3 Max | 36 GB | 6-bit Slow | 6–10 |
| M3 Pro | 36 GB | 6-bit Slow | 3–5 |
| M3 | 16 GB | 2-bit Slow | 5–9 |
| M2 Ultra | 64 GB | 8-bit Runs well | 11–20 |
| M2 Max | 32 GB | 4-bit Runs well | 11–19 |
| M2 Pro | 32 GB | 4-bit Slow | 5–9 |
| M2 | 16 GB | 2-bit Slow | 5–9 |
| M1 Ultra | 64 GB | 8-bit Runs well | 11–20 |
| M1 Max | 32 GB | 4-bit Runs well | 11–19 |
| M1 Pro | 32 GB | 4-bit Slow | 5–9 |
| M1 | 16 GB | 2-bit Slow | 3–6 |
How to run it
- The easy way: download MLX Harness, free and open source. Search for Granite 4.2 30B, download the version that fits your Mac, and chat. It also serves the model to your other apps over an OpenAI-compatible API.Download MLX HarnessFree · Apple Silicon · macOS 14.5 or later
- In Terminal with Apple’s MLX: There is no community MLX build yet, so make one from the official weights:
pip install mlx-lmmlx_lm.convert --hf-path ibm-granite/granite-4.2-30b -q
Step by step: download and run LLMs on a Mac · how to use MLX Harness · MLX vs Ollama vs llama.cpp
About Granite 4.2 30B
| Made by | IBM |
|---|---|
| Parameters | 30B (dense) |
| Context | 128K tokens |
| Licence | Apache-2.0 |
| Released | 2026-08 |
| Input | Text |
| Intelligence | 12.7 on the Artificial Analysis Intelligence Index |
| Weights | ibm-granite/granite-4.2-30b |
Questions
- How much memory does Granite 4.2 30B need?
- About 16.9 GB of weights at 4-bit, plus room for the context: 18.4 GB in all. On a Mac that means 32 GB of unified memory or more, since macOS lets the GPU use about 75% of it by default.
- How fast is Granite 4.2 30B on a Mac?
- Writing speed depends on memory bandwidth. The fastest Mac for it here is an M5 Ultra with 96 GB at about 17–30 tokens a second (8-bit). The smallest Mac that runs it, with 32 GB, manages about 11–19 on an M2 Max.
- Does quantization hurt Granite 4.2 30B?
- At 4 bits most models stay close to the original quality; below 4 bits quality drops faster. Pick the highest precision that fits your Mac with room to spare.
Similar models
For your model card or README
Shows the smallest Mac that runs Granite 4.2 30B well and links here.
[](https://mlx.app/run/granite-4.2-30b)How it’s worked out
Memory: the model’s parameters at 8, 6, 4, 3 or 2 bits per weight plus MLX’s group scales (half a bit per weight), or its native format, with room for the context on top. By default macOS lets the GPU use about 75% of unified memory. Speed: memory bandwidth divided by the bytes read per token is the ceiling for one conversation; in llama.cpp’s public Apple Silicon benchmarks real runs reach about 45% to 80% of it, which is the range shown. These are estimates, not measurements: measure your own Mac on MLX Bench. Model figures from each official model card, chip figures from Apple’s Tech Specs. Checked 2026-10-19. Same data as mlx.app/compare.