text model · gpt-oss · macOS
Can I run gpt-oss 20B on Apple M2 (16GB)?
No. gpt-oss 20B needs ~13.2 GB even at Q4_K_M, but Apple M2 (16GB) only has ~10.5 GB usable.
Needs ~13.2 GB even at Q4_K_M, but only ~10.5 GB is usable.
That figure is at a 4k context and moves about ±15% as context length changes.
The gap is about 2.7 GB: gpt-oss 20B needs roughly 13.2 GB at Q4_K_M and Apple M2 (16GB) leaves only about 10.5 GB usable for a model. The lightest tracked hardware that runs gpt-oss 20B is the Nvidia GeForce RTX 4060 Ti (16GB) at 16 GB. See gpt-oss 20B on Nvidia GeForce RTX 4060 Ti (16GB).
- Q4_K_M needed
- ~13.2 GB
- Usable on device
- ~10.5 GB
- Device memory
- 16 GB
Which quant fits
- Parameters
- 21B (MoE, 3.6B active)
- Q4_K_M size
- 11.28 GB
- Q8_0 size
- 0.86 GB
- Context
- 128k
- Ollama tag
- gpt-oss:20b
- Memory
- 16 GB unified
- Usable for weights
- ~10.5 GB
- Power draw
- ~50 W
- Best runtime
- Ollama (llama.cpp Metal backend) / MLX
What you can run instead
Run gpt-oss 20B on other hardware
FAQ
Can Apple M2 (16GB) run gpt-oss 20B?
No. gpt-oss 20B needs ~13.2 GB even at Q4_K_M, but Apple M2 (16GB) only has ~10.5 GB usable.
How much memory does gpt-oss 20B need?
Apple M2 (16GB) does not have enough memory. At Q4_K_M the weights are ~11.28 GB; with KV cache and runtime overhead, budget ~13.2 GB at a 4k context. It is a Mixture-of-Experts model (21B total / 3.6B active), so all experts must stay in memory; memory tracks total params, not active params.
What is the best tool to run gpt-oss 20B on macOS?
LM Studio for a simple setup; mlx-lm for the most speed. vLLM is NOT a Mac tool, it is a CUDA/Linux serving engine. Unified memory is not a fixed VRAM slice; ~70% is usable for weights.
Embed this
A live badge for your model card or README, updated as the data is. [](https://localmodel.run/can-i-run/gpt-oss-20b/apple-m2-16gb) Sources
- apple.com/newsroom/2022/06
- apple.com/newsroom/2022/07
- developer.apple.com
- github.com/ml-explore
- github.com/raullenchai
- huggingface.co/ggml-org
- huggingface.co/openai
- lmstudio.ai
- ollama.com/library/gpt-oss
- ollama.com/library/gpt-oss/tags
- stencel.io
- support.apple.com/en-us/103253
- support.apple.com/en-us/111869
Weights are measured from GGUF files; KV cache and overhead are computed, so totals can vary ~15% with context and runtime. Any tok/s is a bandwidth estimate. See methodology.