Can I Run Llama 3.1 405B Instruct on a Apple M5 Ultra (512GB)?
Runs at Q8_0 — near-lossless quality.
4 quantizations fit your 512GB
| Quant | Min VRAM | Recommended | File size | Headroom |
|---|---|---|---|---|
| Q8_0BEST | 432.3 GB | 433.8 GB | 431.3 GB | +79.7 GB |
| Q6_K | 335.4 GB | 336.9 GB | 334.4 GB | +176.6 GB |
| Q5_K_M | 289.2 GB | 290.7 GB | 288.2 GB | +222.8 GB |
| Q4_K_M | 247.1 GB | 248.6 GB | 246.1 GB | +264.9 GB |
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Top-ranked open-source models that fit in 512GB.
FAQ
Can the Apple M5 Ultra (512GB) run Llama 3.1 405B Instruct?
Yes. The Apple M5 Ultra (512GB)'s 512GB of unified memory is enough to run Llama 3.1 405B Instruct at Q8_0 quantization (432.3GB required).
What's the best quantization to use?
Q8_0 is the highest-precision quantization that fits in your 512GB. It uses about 432.3GB of memory and 433.8GB recommended for comfortable inference.
What if I need more headroom for context length?
KV cache memory grows with context length. The numbers above assume a baseline 2K-4K context. For long-context use (32K+), add another 2-6GB depending on the model architecture.