How fast will Gemma 4 31B feel on the Mac Studio M5 Ultra 512GB?

Gemma 4 31B on the Mac Studio M5 Ultra 512GB

Gemma 4 31B is a 31.27B-parameter model. At Q4_K_M it needs about 19.1 GB of memory. The Mac Studio M5 Ultra 512GB has 384 GB usable, so it fits entirely in memory. Expect about 31 tokens/sec (26–36), with the first token after 0.4 s for a short prompt. This estimate is projected from the hardware specs; no benchmarks exist yet.

Speed by quantization

QuantizationFile sizeMemoryGenerationFirst tokenSource
Q4_K_M18.3 GBFits31 tok/s0.4 sProjected
Q8_032.6 GBFits17 tok/s0.4 sProjected
FP1661.4 GBFits9.2 tok/s0.4 sProjected

Gemma 4 31B on other hardware

Other models on the Mac Studio M5 Ultra 512GB

All models on the Mac Studio M5 Ultra 512GB · Gemma 4 31B 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.