Rig Finder index / 70B / Local RAG / knowledge base / Iowa
Best rig to run a 70B model for local rag / knowledge base in Iowa
For a 70B model at this workload, the RTX 3090 (used) pays off fastest — break-even ~6 months, keeping $6,180 over 3 years versus Claude Sonnet 4.6.
Same workload, same cloud, same electricity — we swap only the hardware and rank by real break-even. Rigs that can't run a 70B model are shown, never recommended. Compared against Claude Sonnet 4.6 ($3/M in, $15/M out); change the cloud in the lab.
Every build, ranked
| Rig | Build | 70B tok/s | Local/mo | Break-even | Verdict |
|---|---|---|---|---|---|
| RTX 3090 (used)best payoff | $1,200 | 6estimated | $44.34 | ~6 mo | OWN |
| RTX 4090 | $2,300 | 8estimated | $76.09 | ~11 mo | OWN |
| 2× RTX 3090 | $2,250 | 15estimated | $81.13 | ~11 mo | OWN |
| Mac M-series | $3,000 | 9estimated | $85.53 | ~14 mo | OWN |
| RTX 5090 | $3,500 | 14estimated | $113 | ~17 mo | OWN |
| Mini-PCtoo small for 70B | $750 | — | $23.22 | ~4 mo | OWN |
Assumes local rag / knowledge base use: ~40M tokens/month, 5h/day active, 11h/day idle, at Iowa electricity ($0.131/kWh). Speeds are our estimates; community-measured tok/s live on the interactive Rig Finder and the benchmarks board. Every formula is on the methodology page.
Run this with your exact numbers →