Ollama Auto-Enables Qwen3.5 MTP on Macs, MLX Backend Shows Major Speedup

BTA_Labs · reddit · 2026-08-05

Ollama's latest v0.32.6-rc0 release introduces a major inference optimization for Apple Silicon users: when a Qwen3.5 model includes built-in MTP (Multi-Token Prediction) tensors, Ollama’s MLX backend automatically loads the head and uses the model as its own speculative draft, requiring no extra configuration.

Adaptive Speculative Depth

The MTP head proposes one token per step, while Ollama’s controller dynamically adjusts the speculative depth based on measured cost and acceptance rate. The new build also logs detailed per-request stats, including tokens drafted/accepted, acceptance rate, and average/max draft depth.

Backend Discrepancy

Although Ollama simply notes that "Qwen3.5 is faster on Apple GPUs," the community noted that a previous llama.cpp Metal backend test showed an 11–27% regression using MTP (dropping from 25.3 tok/s to 19.3 tok/s on an M1 Max). The author points out that Ollama previously reported a 90% speedup for Gemma 4 using its MLX MTP implementation, suggesting the backend and adaptive depth controller matter more than MTP support itself. Standardized benchmarks are still needed to compare the real differences between MLX and Metal backends.

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