Gemini 3 Pro Preview vs Xai Grok 4.20 Reasoning
Gemini 3 Pro Preview vs Xai Grok 4.20 Reasoning: Xai Grok 4.20 Reasoning is cheaper by 50% on average. Gemini 3 Pro Preview from Google Vertex AI (1,048,576-token context, reasoning, tool calls) vs. Xai Grok 4.20 Reasoning from Google Vertex AI (2,000,000-token context, reasoning, tool calls). Use Agent Command Center to A/B both in shadow mode and pick the winner per workload.
Side-by-side cost
Live workload comparison
Same workload run through both models. The cheaper one is highlighted.
3,000
02,000,000
400
0200,000
5,000
01,000,000
At this workload, Xai Grok 4.20 Reasoning is 22% cheaper than Gemini 3 Pro Preview — a savings of $365/month ($4,383/year).
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
model: xai-grok-4-20-reasoning
provider: vertex-ai
fallback:
model: gemini-3-pro-preview
provider: vertex-ai
shadow: { sample_rate: 0.05 } # mirror 5% of traffic to compare quality live| Gemini 3 Pro Preview | Xai Grok 4.20 Reasoning | |
|---|---|---|
| Input price | $2.00/M | $2.00/M |
| Output price | $12.00/M | $6.00/M |
| Context window | 1,048,576 | 2,000,000 |
| Max output | 65,535 | 2,000,000 |
| Function calling | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio input | ✓ | — |
| Reasoning | ✓ | ✓ |
| Prompt caching | ✓ | — |
| Structured output | ✓ | ✓ |
| Pricing verified | May 12, 2026 | May 12, 2026 |
Benchmark comparison
Side-by-side public benchmark scores. Greener bar = winner.
Chatbot Arena ELOgeneral
Gemini 3 Pro Preview
1,486
Xai Grok 4.20 Reasoning
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