Break-even index / RTX 4090 / Claude Sonnet 4.6 / Alabama
Will a New RTX 4090 build beat Claude Sonnet 4.6 in Alabama?
Break-even lands around month 18. Real, but slow — a hybrid setup (local for the routine work, cloud for the peaks) usually beats going all-in.
How to read it: OWN — the rig pays for itself inside 18 months. HYBRID — break-even lands between 18 and 36 months; real, but slow. RENT — it never pays off before the hardware is due for replacement. Every formula and threshold is public on the methodology page.
The numbers
| Build cost (New RTX 4090 build) | $2,300 ($2,000–$2,600) |
|---|---|
| Hardware amortized (3 yr) | $63.89/mo |
| Electricity in Alabama ($0.162/kWh) | $8.63/mo (53.25 kWh) |
| Local total cost of ownership | $72.52/mo |
| Claude Sonnet 4.6 at the same usage | $135/mo |
| Break-even | about 18 months |
Assumes the "coding assistant" preset: ~15M tokens/month, 3 h/day active, 5 h/day idle. Claude Sonnet 4.6 priced at $3/M in, $15/M out (verified 2026-07-05). Rig ceiling: 70B at Q4, faster prompt processing. Jargon: VRAM is the GPU memory that decides which models fit; Q4 is 4-bit quantization — a smaller, faster copy of a model with a slight quality cost.
See your verdict — then tweak every number →