Tip: Qwen3.5 ROCm vs Vulkan Benchmarks on AMD GPUs — ROCm Wins Prompt Processing, Context Size Matters More Than Backend

r/LocalLLaMA·medium signal

A practitioner benchmarked Qwen3.5 (35B MoE, 27B Dense, 122B MoE) across Apple Silicon and AMD GPUs, finding ROCm outperforms Vulkan for prompt processing on AMD hardware. The surprising result: context size has a larger impact on throughput than the choice of compute backend. MacBook Pro M-series performance is competitive with AMD desktop GPUs for the smaller models. With 71 upvotes and 46 comments, the post includes specific tok/s numbers across all configurations — useful for anyone choosing between Apple and AMD for local inference.