Can Mac Pro M2 Ultra 64 GB run GLM-5.3-Flash (320B-A18B)?
64 GB unified · 800 GB/s memory bandwidth · GLM-5.3-Flash (320B-A18B) has 320B parameters (18B active per token).
Short answer
No. It doesn't fit in memory.
Needs ≈133 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 (3-bit) needs about 133 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 Pro M2 Ultra 64 GB has about 54 GB left, so it’s 79 GB short.
Ways to make it work
Close everything else
Not enough on its own: with every other app closed it’s still about 76 GB short.
Pick a smaller model from the same family
Get more memory
The same chip with 192 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 Pro M2 Ultra 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.
Other models for Mac Pro M2 Ultra 64 GB
The best-rated models for chat on this machine.
- Qwen3.6 35B-A3B100–130 tok/sExcellent
- Qwen3-Next 80B-A3B Instruct140–190 tok/sExcellent
- Gemma 4 26B-A4B80–110 tok/sExcellent
- Qwen3.5 35B-A3B100–130 tok/sExcellent
- LFM2.5 24B-A2B190–260 tok/sExcellent
- gpt-oss-20b120–160 tok/sExcellent
Cheapest machines for GLM-5.3-Flash (320B-A18B)
Hardware rated comfortable or better for chat, lowest price first.
Different tool, context size or workload?
These pages use typical settings. The full check models your exact setup.