Local AI Advisor

Can Mac mini M4 32 GB run gpt-oss-20b?

32 GB unified · 120 GB/s memory bandwidth · gpt-oss-20b has 20.9B parameters (3.6B active per token).

Short answer

Yes, excellent for chat and acceptable or better for every workload we test.

Best quantization for chat: MXFP4 (11 GB of weights) on LM Studio. Generation: 25–35 tok/s, leaving about 12 GB free for your other apps.

How it rates for each workload

Same model and machine, different jobs. Agents and long documents send far bigger prompts than chat, so they need much more speed and memory.

WorkloadVerdictQuantGenerationFirst replyContext
Chatwith Open WebUIExcellentMXFP425–35 tok/s≈2 s8KDetails
Coding questionswith ContinueExcellentMXFP425–35 tok/s≈10 s16KDetails
Coding in a repositorywith AiderAcceptableMXFP425–30 tok/s≈40 s32KDetails
Agentic codingwith OpenCodeAcceptableMXFP420–30 tok/s≈55 s32KDetails
Long documents (64K)with Open WebUIAcceptableMXFP417–25 tok/s≈3 min64KDetails

Speeds are estimates calibrated against measured benchmarks on similar hardware. “First reply” is the time to read the workload’s opening prompt. How we calculate

Get it running

Copy-paste commands for the MXFP4 build with a 64K context. Ollama and llama.cpp download the file straight from Hugging Face.

ollama run hf.co/unsloth/gpt-oss-20b-GGUF:F16

Downloads 13.79 GB (F16). Ollama's default context is small: set OLLAMA_CONTEXT_LENGTH=65536 before `ollama serve` for long prompts.

Different tool, context size or workload?

These pages use typical settings. The full check models your exact setup.