Rig Finder index / 70B / Always-on agent server / Montana
Best rig to run a 70B model for always-on agent server in Montana
For a 70B model at this workload, the RTX 3090 (used) pays off fastest — break-even ~2 months, keeping $21,847 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 | $53.15 | ~2 mo | OWN |
| 2× RTX 3090 | $2,250 | 15estimated | $95.88 | ~4 mo | OWN |
| RTX 4090 | $2,300 | 8estimated | $85.87 | ~4 mo | OWN |
| Mac M-series | $3,000 | 9estimated | $87.30 | ~5 mo | OWN |
| RTX 5090 | $3,500 | 14estimated | $125 | ~6 mo | OWN |
| Mini-PCtoo small for 70B | $750 | — | $25.09 | ~1 mo | OWN |
Assumes always-on agent server use: ~120M tokens/month, 10h/day active, 14h/day idle, at Montana electricity ($0.127/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.
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