Memory at each precision
| Version | Weights | With context | Smallest Mac |
|---|---|---|---|
| 8-bit | 15.9 GB | 17.4 GB | 24 GB |
| 6-bit | 12.2 GB | 13.7 GB | 24 GB |
| 4-bit | 8.4 GB | 9.9 GB | 16 GB |
| 3-bit lower quality | 6.6 GB | 8.1 GB | 16 GB |
| 2-bit lower quality | 4.7 GB | 6.2 GB | 16 GB |
On every Apple chip
The smallest memory size of each chip that runs Phi-4 Reasoning Vision 15B, the best version that fits it, and the writing speed you can expect.
| Chip | Needs | Version | Tokens/s |
|---|---|---|---|
| M6 | 16 GB | 4-bit Slow | 8–15 |
| M5 Ultra | 96 GB | 8-bit Runs well | 34–60 |
| M5 Max | 36 GB | 8-bit Runs well | 13–23 |
| M5 Pro | 24 GB | 6-bit Runs well | 11–20 |
| M5 | 16 GB | 4-bit Slow | 8–15 |
| M4 Max | 36 GB | 8-bit Runs well | 12–21 |
| M4 Pro | 24 GB | 6-bit Runs well | 10–18 |
| M4 | 16 GB | 4-bit Slow | 6–11 |
| M3 Ultra | 96 GB | 8-bit Runs well | 23–41 |
| M3 Max | 36 GB | 6-bit Runs well | 11–20 |
| M3 Pro | 18 GB | 4-bit Slow | 8–14 |
| M3 | 16 GB | 4-bit Slow | 5–10 |
| M2 Ultra | 64 GB | 8-bit Runs well | 23–40 |
| M2 Max | 32 GB | 8-bit Runs well | 11–20 |
| M2 Pro | 16 GB | 4-bit Runs well | 11–19 |
| M2 | 16 GB | 4-bit Slow | 5–10 |
| M1 Ultra | 64 GB | 8-bit Runs well | 23–40 |
| M1 Max | 32 GB | 8-bit Runs well | 11–20 |
| M1 Pro | 16 GB | 4-bit Runs well | 11–19 |
| M1 | 16 GB | 4-bit Slow | 4–6 |
How to run it
- The easy way: download MLX Harness, free and open source. Search for Phi-4 Reasoning Vision 15B, 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 microsoft/Phi-4-reasoning-vision-15B -q
Step by step: download and run LLMs on a Mac · how to use MLX Harness · MLX vs Ollama vs llama.cpp
About Phi-4 Reasoning Vision 15B
| Made by | Microsoft |
|---|---|
| Parameters | 15B (dense) |
| Context | 16K tokens |
| Licence | MIT |
| Released | 2026-03 |
| Input | Text and images |
| Weights | microsoft/Phi-4-reasoning-vision-15B |
Questions
- How much memory does Phi-4 Reasoning Vision 15B need?
- About 8.4 GB of weights at 4-bit, plus room for the context: 9.9 GB in all. On a Mac that means 16 GB of unified memory or more, since macOS lets the GPU use about 75% of it by default.
- How fast is Phi-4 Reasoning Vision 15B on a Mac?
- Writing speed depends on memory bandwidth. The fastest Mac for it here is an M5 Ultra with 96 GB at about 34–60 tokens a second (8-bit). The smallest Mac that runs it, with 16 GB, manages about 11–19 on an M2 Pro.
- Does quantization hurt Phi-4 Reasoning Vision 15B?
- 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 Phi-4 Reasoning Vision 15B well and links here.
[](https://mlx.app/run/phi-4-reasoning-vision-15b)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.