GLM-5.3 Flash is a 321.3B-parameter mixture-of-experts model (18B active per token). At Q4_K it needs about 182.1 GB of memory. The Mac Studio M5 Ultra 256GB has 192 GB usable, so it fits entirely in memory. Expect about 63 tokens/sec (36–90), with the first token after 0.3 s for a short prompt. This estimate is interpolated from benchmarks of similar setups.
| Quantization | File size | Memory | Generation | First token | Source |
|---|---|---|---|---|---|
| UD-IQ1_S | 93.1 GB | Fits | 118 tok/s | 0.3 s | Derived |
| UD-IQ1_M | 97.6 GB | Fits | 116 tok/s | 0.3 s | Derived |
| UD-IQ2_XXS | 101.8 GB | Fits | 112 tok/s | 0.3 s | Derived |
| UD-Q2_K_XL | 108.7 GB | Fits | 105 tok/s | 0.3 s | Derived |
| UD-IQ3_XXS | 120.4 GB | Fits | 95 tok/s | 0.3 s | Derived |
| UD-Q3_K_XL | 147.5 GB | Fits | 77 tok/s | 0.3 s | Derived |
| UD-IQ4_XS | 156.8 GB | Fits | 73 tok/s | 0.3 s | Derived |
| Q4_K | 181.4 GB | Fits | 63 tok/s | 0.3 s | Derived |
| UD-Q4_K_XL | 199.7 GB | Doesn't fit | Won't run | — | — |
| UD-Q5_K_XL | 240.3 GB | Doesn't fit | Won't run | — | — |
| UD-Q6_K_XL | 291.8 GB | Doesn't fit | Won't run | — | — |
| Q8_0 | 341.0 GB | Doesn't fit | Won't run | — | — |
| FP16 | 642.8 GB | Doesn't fit | Won't run | — | — |
All models on the Mac Studio M5 Ultra 256GB · GLM-5.3 Flash 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.