Gemma 4 MTP Slows Down on Dual 3090s
DjCanalex · reddit · 2026-07-19
The author tested the MTP (draft/multi-token prediction) performance of Gemma 4 31B QAT on dual and single RTX 3090 setups, concluding that it actually slows down in a dual-GPU environment.
Observed Results
- Dual 3090s: 39.7 t/s without MTP, dropping to a fluctuating 27–34 t/s with MTP enabled
- Single 3090: 33 t/s without MTP, initially jumping to 45 t/s with MTP enabled, then gradually settling at 36–37 t/s
Additional Logs
- Dual-GPU setup: draft acceptance rate of 0.56, mean length of 2.22
- Single-GPU setup: draft acceptance rate of 0.56, mean length of 2.29
The author shared output logs for both configurations along with their llama-server startup commands, seeking to understand why MTP performance on multiple GPUs contradicts the single-GPU results.
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