Break-even index / 2× RTX 3090 / Claude Opus 4.8 / Rhode Island
Will a Dual used RTX 3090 beat Claude Opus 4.8 in Rhode Island?
Your rig pays for itself in 11 months — after that you bank roughly $138/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 (Dual used RTX 3090) | $2,250 ($2,000–$2,500) |
|---|---|
| Hardware amortized (3 yr) | $62.50/mo |
| Electricity in Rhode Island ($0.301/kWh) | $24.38/mo (81 kWh) |
| Local total cost of ownership | $86.88/mo |
| Claude Opus 4.8 at the same usage | $225/mo |
| Break-even | about 11 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: 70B at Q4, comfortably. 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 →