Why LlamaBox defaults to CPU inference
GPU acceleration sounds better on paper. For Android, CPU-first is the more compatible default — and the one that reaches the most users.
Every local LLM project eventually faces the GPU question. On Android, the honest answer is that GPU compute is a gamble, not a guarantee.
The driver lottery
OpenCL support varies by chipset, vendor, Android version, and sometimes carrier build. A Snapdragon 8 Gen 3 may expose a compute path that a MediaTek Dimensity or an older Exynos does not. The same app, same model, same GGUF file can behave differently on two phones that look identical in a spec sheet.
The user-visible cost
A “GPU acceleration” toggle that fails silently is worse than no toggle at all. Users blame the app, leave a one-star review, and uninstall. The CPU path is predictable: slower tokens, but the same tokens on every supported device.
What CPU-first execution means
LlamaBox uses llama.cpp’s ARM CPU path with a configurable thread count. CPU execution is the compatibility baseline; actual performance depends on the phone, model and context.
Honest exceptions
- Flagship users with working GPU drivers could get faster generation
- Vision encoding uses the CPU in the current multimodal path
- Future hardware may make a GPU path worth revisiting — but only after real-device validation
The bottom line
CPU remains the default compatibility path; acceleration is experimental and device-dependent. Read more in architecture.
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