Part 1 established the hardware, the runner, and the primary model. This entry covers what governs inference on that hardware — the two phases of inference, the cost of long context, and the cost of loading a model from disk — and compares the local machines against a free-tier cloud model. The two phases of inference Inference has two phases. Prefill processes the input prompt before any output appears; it is compute-bound and wants a GPU. Generation produces output tokens o...