REDDIT · REDDIT// 32d agoINFRASTRUCTURE

llama.cpp users flag Metal slowdown on Intel Macs

A Reddit post in r/LocalLLaMA highlights extremely poor `llama.cpp` inference performance on an Intel Mac Pro with an RX 580 under Metal, with the user reporting under 1 token per second and less than 2% GPU utilization. The complaint stands out because the same hardware reportedly reaches 20+ tokens per second under Vulkan on Linux and Windows, turning the thread into a sharp reminder that Apple’s older Intel-era GPU path remains a weak spot for local LLM inference.

// ANALYSIS

This is less a product update than a reality check on backend fragmentation: `llama.cpp` is broad and fast, but not every hardware/software combo gets first-class treatment.

–The `llama.cpp` project explicitly positions Apple Silicon as a first-class target, which helps explain why Intel Mac + AMD GPU setups can feel like second-tier citizens.
–The gap between Metal on macOS and Vulkan on Linux/Windows suggests the bottleneck is backend maturity and driver behavior, not just raw GPU capability.
–MoltenVK shows why developers keep chasing a cross-platform graphics stack, but shader failures also show how messy that portability story still is on Macs.
–Even with aggressive offload flags like `-ngl 999`, backend limitations can dominate performance, so tuning alone may not rescue older Intel Mac configurations.

// TAGS

llama-cppllminferencegpuopen-source

DISCOVERED

32d ago

2026-03-10

PUBLISHED

36d ago

2026-03-07

RELEVANCE

6/ 10

AUTHOR

FreQRiDeR