Qwen 27B strains 24GB MacBooks

Running a 27B parameter dense model on 24GB of unified memory is operating at the absolute edge of Apple Silicon's limits, leaving almost no room for the context window.

• –macOS reserves around 20-30% of unified memory for system tasks, leaving only 16-18GB available for the GPU.
• –A 4-bit quantized 27B model requires roughly 16-17GB of RAM, creating a tight squeeze that frequently leads to swapping or crashing on 24GB machines.
• –While MLX is highly optimized for Apple Silicon, users often need to manually increase the macOS GPU memory allocation limit via terminal commands to run dense models comfortably.
• –A more practical alternative for 24GB hardware is adopting Mixture-of-Experts (MoE) models, which offer similar reasoning capabilities but require significantly less VRAM for active parameters.