GLM-5.3 is a 753.33B-parameter mixture-of-experts model (39B active per token). At UD-IQ1_S it needs about 217.5 GB of memory. The Mac Studio M5 Ultra 256GB has 192 GB usable, so it doesn't fit, even at its smallest quantization.
| Quantization | File size | Memory | Generation | First token | Source |
|---|---|---|---|---|---|
| UD-IQ1_S | 216.7 GB | Doesn't fit | Won't run | — | — |
| UD-Q2_K_XL | 253.9 GB | Doesn't fit | Won't run | — | — |
| UD-IQ3_XXS | 281.7 GB | Doesn't fit | Won't run | — | — |
| UD-Q3_K_XL | 343.0 GB | Doesn't fit | Won't run | — | — |
| UD-IQ4_XS | 365.3 GB | Doesn't fit | Won't run | — | — |
| UD-Q4_K_XL | 467.3 GB | Doesn't fit | Won't run | — | — |
| Q8_0 | 801.4 GB | Doesn't fit | Won't run | — | — |
| FP16 | 1508.0 GB | Doesn't fit | Won't run | — | — |
All models on the Mac Studio M5 Ultra 256GB · GLM-5.3 on all hardware
Estimates for a short prompt on a single device. Measured numbers come from community benchmarks (r/LocalLLaMA, localscore.ai and more); others are derived from similar setups or projected from specs. Open source on GitHub.