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GPT-5.5 Pro vs Grok 4.20 Multi-Agent

How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for GPT-5.5 Pro and Grok 4.20 Multi-Agent.

OpenAI

GPT-5.5 Pro

GPT-5.5 Pro is OpenAI’s high-capability model optimized for deep reasoning and accuracy on complex, high-stakes workloads. It features a 1M+ token context window (922K input, 128K output) with support for...

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xAI

Grok 4.20 Multi-Agent

Grok 4.20 Multi-Agent is a variant of xAI’s Grok 4.20 designed for collaborative, agent-based workflows. Multiple agents operate in parallel to conduct deep research, coordinate tool use, and synthesize information...

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Technical Specifications

SpecificationGPT-5.5 ProGrok 4.20 Multi-Agent
ProviderOpenAIxAI
Context Window1,050,000 tokens2,000,000 tokens
Agent Suitability98/100N/A
Time to First Token (TTFT)450 msN/A
Deployment Modelmanaged apimanaged api
Production Stabilitybetabeta
API AvailableYesYes
Released Date2026-04-242026-03-31

API Pricing Comparison

Input Price per Million Tokens

GPT-5.5 Pro

$30.00

Grok 4.20 Multi-Agent

$1.25

Output Price per Million Tokens

GPT-5.5 Pro

$180.00

Grok 4.20 Multi-Agent

$2.50

Want to test both models live?

Run side-by-side prompt prompts in our dynamic Sandbox. Check execution speeds, latency metrics, and compute actual costs in real-time.

Benchmark Performance Metrics

Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.

MMLUGeneral knowledge & multi-task understanding
9650.0%vsN/A
GPT-5.5 Pro
Grok 4.20 Multi-Agent
HumanEvalPython coding & logic synthesis
9820.0%vsN/A
GPT-5.5 Pro
Grok 4.20 Multi-Agent
MATHComplex mathematical problem solving
9600.0%vsN/A
GPT-5.5 Pro
Grok 4.20 Multi-Agent
GPQAGraduate-level expert reasoning
8910.0%vsN/A
GPT-5.5 Pro
Grok 4.20 Multi-Agent
HellaSwagCommonsense reasoning and inference
9940.0%vsN/A
GPT-5.5 Pro
Grok 4.20 Multi-Agent
MT-BenchMulti-turn conversation flow quality
990.0%vsN/A
GPT-5.5 Pro
Grok 4.20 Multi-Agent

GPT-5.5 Pro Quirks & Gotchas

  • Best-in-class instruction following for complex agentic chains
  • Premium pricing — use GPT-5 for cost-sensitive workloads

Grok 4.20 Multi-Agent Quirks & Gotchas

No developer gotchas reported.