Sonnet orchestrating local Qwen 3.8 27B cuts costs 2.7x but drops quality from 4/5 to 2/5

GapNew4766 · reddit · 2026-09-29

Testing the popular "cheap local model + expensive cloud model" split on 5 physics-scene builds with one identical prompt: Sonnet 5.5 alone cost $1.83 in 9 min (4/5 scenes), local Qwen 3.8 27B on a 3090 cost $0 in 26 min (1/5, hollow teleporting cubes), and fusion mode — Sonnet writing briefs (5.4K tokens vs 37.9K), Qwen writing all code — cost $0.67 in 85 min (2/5). Reversing roles (Qwen plans, Sonnet codes) hit 4/5 in 14 min but cost more than Sonnet alone since every cloud worker re-reads context. Verdict: the split really cuts the bill 2.7x, paid for in time and quality.

Related event: Cloud-Planning Plus Local-Execution Cuts Costs 2.7x but Takes 9x Longer(3 posts)→

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