grok-4-fast-chat vs grok-4.20-multi-agent-beta-0309 Benchmark Comparison

Direct benchmark comparison between grok-4-fast-chat and grok-4.20-multi-agent-beta-0309 based on LMArena Elo and the latest 2026 API pricing.

Direct Technical & Pricing Comparison

Frontier Model	LMArena Elo	API Cost (1M)	Throughput
grok-4-fast-chat	1421	$2e-7	168
grok-4.20-multi-agent-beta-0309	1476	$0.000002	709

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

Comparison Summary: grok-4.20-multi-agent-beta-0309 is the more capable model in this pair, leading by 55 Elo points. However, neither model is currently Pareto-optimal. Developers looking for peak efficiency should investigate gpt-5.2-chat-latest-20260210, which offers a superior benchmark-to-price ratio.