Agent Arena Pareto frontier: DeepSeek V4.1 Flash delivers +4.1% at just $0.06 per task

arena · x · 2026-09-26

Agent Arena's cost-vs-performance Pareto frontier maps net improvement against median cost per task:

Pareto-optimal tier: Claude Fable 5.1 (Max) +13.80%/$4.11, GPT 6 Astra (Max) +10.85%/$2.82, Claude Opus 5 (High) +9.80%/$2.15, Claude Fable 5 (High) +8.28%/$1.71, GPT 6 Sol (Max) +7.68%/$0.74, Claude Sonnet 5 (High) +4.79%/$0.70.

The budget tier is dominated by Chinese models: Kimi K3 (Max) +4.55%/$0.67, Tencent Hy4 preview +4.37%/$0.17, DeepSeek V4.1 Flash (Max) +4.10%/$0.06, plus Tencent Hy3 and Xiaomi Mimo V2.5 Pro at $0.04 with negative net improvement. Gemini 3.8 Flash and GLM 5.2 also make the top 15.

Related event: Agent Arena Launches Real-World Agent Leaderboard; Claude Fable 5.1 Tops Rankings(4 posts)→

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