Can I Run / GPT-OSS 20B / on Apple M3 Max (36GB)

Can I Run GPT-OSS 20B on a Apple M3 Max (36GB)?

Yes

Runs at Q8_0 — near-lossless quality.

Model size
20.0B
GPU memory
36.0GB
Smallest quant
Q4_K_M
Best fit
Q8_0

4 quantizations fit your 36.0GB

QuantMin VRAMRecommendedFile sizeHeadroom
Q8_0BEST22.3 GB23.8 GB21.3 GB+13.8 GB
Q6_K17.5 GB19.0 GB16.5 GB+18.5 GB
Q5_K_M15.2 GB16.7 GB14.2 GB+20.8 GB
Q4_K_M13.1 GB14.6 GB12.1 GB+22.9 GB

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Full model details
GPT-OSS 20B

All quant variants, benchmark scores, and use-case tags.

Best models for this GPU
Apple M3 Max (36GB)

Top-ranked open-source models that fit in 36.0GB.

FAQ

Can the Apple M3 Max (36GB) run GPT-OSS 20B?

Yes. The Apple M3 Max (36GB)'s 36.0GB of unified memory is enough to run GPT-OSS 20B at Q8_0 quantization (22.3GB required).

What's the best quantization to use?

Q8_0 is the highest-precision quantization that fits in your 36.0GB. It uses about 22.3GB of memory and 23.8GB 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.