Break-even index / Mac M-series / Claude Opus 4.8 / Rhode Island
Will a Mac (M-series, unified memory) beat Claude Opus 4.8 in Rhode Island?
Your rig pays for itself in 14 months — after that you bank roughly $139/mo versus the cloud. Clear win.
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 (Mac (M-series, unified memory)) | $3,000 ($2,000–$4,000) |
|---|---|
| Hardware amortized (3 yr) | $83.33/mo |
| Electricity in Rhode Island ($0.301/kWh) | $2.89/mo (9.6 kWh) |
| Local total cost of ownership | $86.22/mo |
| Claude Opus 4.8 at the same usage | $225/mo |
| Break-even | about 14 months |
Assumes the "coding assistant" preset: ~15M tokens/month, 3 h/day active, 5 h/day idle. Claude Opus 4.8 priced at $5/M in, $25/M out (verified 2026-07-05). Rig ceiling: Up to 70B via unified memory (slower 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 →