They initially messed up this launch and overwrote some of the GGUF models in their library, making them non-downloadable on platforms other than Apple Silicon. Hopefully that gets fixed.

How many tokens per second?

Roughly 8-12 token/s on generation depending on context length. Prompt processing is faster obviously. Haven't benchmarked it super carefully though, just eyeballing the llama.cpp output.

The key difference is that MLX's array model assumes unified memory from the ground up. llama.cpp's Metal backend works fine but carries abstractions from the discrete GPU world — explicit buffer synchronization, command buffer boundaries — that are unnecessary when CPU and GPU share the same address space. You'll notice the gap most at large context lengths where KV cache pressure is highest.

Insightful comment, thanks!

that tracks with what i've noticed practically. shorter prompts feel basically the same between llama.cpp metal and what i'd expect from native mlx, but once context gets longer the overhead starts showing up. would be interesting to see if ollama's mlx path actually handles kv cache differently under the hood or if it just skips the buffer sync layer

If it's just about skipping some buffer sync that's something that could also be adopted by llama.cpp's own Metal backend, at least on Apple Silicon platforms.