grok-4.20-beta-0309-reasoning vs mimo-v2.5 Benchmark Comparison

Direct benchmark comparison between grok-4.20-beta-0309-reasoning and mimo-v2.5 based on LMArena Elo and the latest 2026 API pricing.

Direct Technical & Pricing Comparison

Frontier Model	LMArena Elo	API Cost (1M)	Throughput
grok-4.20-beta-0309-reasoning	1475	$0.00000125	94
mimo-v2.5	1434	$1.4e-7	41

*These models represent the Pareto Frontier (optimal cost-to-performance).*

Comparison Summary: grok-4.20-beta-0309-reasoning is the more capable model in this pair, leading by 41 Elo points. However, neither model is currently Pareto-optimal. Developers looking for peak efficiency should investigate gpt-5.5, which offers a superior benchmark-to-price ratio.