Apple · 192 GB LPDDR5 · 800 GB/s bandwidth ·
Google · 30.7B · model ctx up to 256K
Yes — the Mac Studio M2 Ultra 192GB (192 GB LPDDR5) can run gemma-4-31B-it. At Q4 with the default 8K context it needs ≈ 24.03 GB VRAM (weights 16.89 GB + KV cache 6.14 GB + 1 GB runtime overhead), which fits within 192 GB. Decode at Q4/8K: ≈ 16.6 tok/s (estimated, batch 1). FP16 (≈ 68.54 GB) also fits, at ≈ 4.6 tok/s (estimated). Estimates come from memory-bandwidth math; rows tagged measured override estimates. Relative ranking is more reliable than absolute tok/s. Methodology.
Fit & speed by quant and context
Quant
Context
VRAM needed
Fits?
tok/s (decode)
Q4
4K
20.96 GB
Yes
16.6est.
Q4
8K default
24.03 GB
Yes
16.6est.
Q4
32K
42.45 GB
Yes
16.6est.
FP16
4K
65.47 GB
Yes
4.6est.
FP16
8K default
68.54 GB
Yes
4.6est.
FP16
32K
86.96 GB
Yes
4.6est.
Fits = weights + KV(ctx) + 1 GB overhead ≤ 95% of VRAM. Measured
anchors are context-agnostic; the fit verdict is recomputed per context. A missing tok/s
means the model is far beyond this card (offload-only territory).