Speculative decoding works great for Gemma 4 31B in llama.cpp

I get a ~11% speed up with Gemma 3 270B as the draft model. Try it by adding:

--no-mmproj -hfd unsloth/gemma-3-270m-it-GGUF:Q8_0 

Testing with (on a 3090):

./build/bin/llama-cli -hf unsloth/gemma-4-31B-it-GGUF:Q4_1 --jinja --temp 1.0 --top-p 0.95 --top-k 64 -ngl 1000 -st -f prompt.txt --no-mmproj -hfd unsloth/gemma-3-270m-it-GGUF:Q8_0 

Gave me:

[ Prompt: 607.3 t/s | Generation: 36.6 t/s ]
draft acceptance rate = 0.44015 ( 820 accepted / 1863 generated)

vs.

[ Prompt: 613.8 t/s | Generation: 32.9 t/s ]