Local AI Advisor

Can Mac Studio M2 Max 64 GB run gpt-oss-120b?

64 GB unified · 400 GB/s memory bandwidth · gpt-oss-120b has 116.8B parameters (5.1B active per token).

Short answer

No. It doesn't fit in memory.

Needs ≈60 GB but only ≈54 GB is available after the OS, other apps and Open WebUI.

Why it doesn’t fit

Even its smallest practical version (MXFP4) needs about 60 GB for the model, its context memory and the runtime. After macOS (≈6.0 GB), a browser with a few tabs (≈3.0 GB) and Open WebUI (≈1.0 GB), Mac Studio M2 Max 64 GB has about 54 GB left, so it’s 6.2 GB short.

Ways to make it work

  • Close everything else

    Not enough on its own: with every other app closed it’s still about 3.2 GB short.

  • Pick a smaller model from the same family

  • Get more memory

    The same chip with 96 GB handles it: Excellent.

  • Check your exact setup

    These pages assume typical settings. A shorter context or a lighter chat app can change the answer.

    Check Mac Studio M2 Max 64 GB

The same applies to every workload we rate (chat, coding questions, coding in a repository, agentic coding and long documents): they all need at least as much memory as chat.

Different tool, context size or workload?

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