Can Mac Studio M5 Max 48 GB run gpt-oss-120b?
48 GB unified · 614 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 ≈39 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 (≈4.8 GB), a browser with a few tabs (≈3.0 GB) and Open WebUI (≈1.0 GB), Mac Studio M5 Max 48 GB has about 39 GB left, so it’s 21 GB short.
Ways to make it work
Close everything else
Not enough on its own: with every other app closed it’s still about 18 GB short.
Pick a smaller model from the same family
Get more memory
The same chip with 128 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 M5 Max 48 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.
Other models for Mac Studio M5 Max 48 GB
The best-rated models for chat on this machine.
- Qwen3.6 35B-A3B110–180 tok/sExcellent
- Gemma 4 26B-A4B70–120 tok/sExcellent
- Qwen3.5 35B-A3B110–180 tok/sExcellent
- LFM2.5 24B-A2B180–300 tok/sExcellent
- gpt-oss-20b110–180 tok/sExcellent
- GLM-4.7-Flash (30B-A3B)90–150 tok/sExcellent
Cheapest machines for gpt-oss-120b
Hardware rated comfortable or better for chat, lowest price first.
- Ryzen AI Max+ 395 mini PC / Framework Desktop · 128 GB$2,000 · 50–70 tok/sExcellent
- Mac Studio M2 Max 96 GB$3,799 · 65–85 tok/sExcellent
- MacBook Pro M3 Max 96 GB$3,999 · 50–65 tok/sExcellent
- Mac Studio M4 Max 128 GB$4,099 · 85–110 tok/sExcellent
- Mac Studio M5 Max 128 GB$4,099 · 80–130 tok/sExcellent
- MacBook Pro M2 Max 96 GB$5,099 · 65–85 tok/sExcellent
Different tool, context size or workload?
These pages use typical settings. The full check models your exact setup.