Lesson 1: What a GPU holds, how fast it feeds, what it costs
21 min read·
Module 7 · Lesson 1 · About 50 minutes · Needs: what a parameter, a batch and an optimiser are (Module 4 lesson 1), and a PyTorch training loop (Module 4 lesson 2). No GPU needed; a free Colab T4 adds one optional measurement.
The situation
Week 7 at Kestrel. Imran sends one line: "What does one training run cost, and do we need to buy GPU time?" Rhys owns the GPU question and wants the answer as arithmetic, not opinion.
Kestrel has two training jobs. The late-risk network from Module 4 has 3,521 parameters and learns from 86,014 training parcels. The message model that Module 12 adapts is SmolLM2-135M, an open model with 134,515,008 parameters. This lesson budgets both, in bytes, FLOPs, hours and dollars, and traces them side by side.