OpenAIGPT-5.6 SolVSxAIGrok 4.20

Analysis by:the whichllmmodel Editorial Team|Updated: June 2026

Our Take

This matchup represents a clear tradeoff between peak intelligence and budget efficiency. GPT-5.6 Sol is noticeably superior (holding a 8.7% average lead in benchmarks), but it carries a significant 3.8x price premium. Choose GPT-5.6 Sol if you need top-tier reasoning or code debugging, but for high-volume pipelines, Grok 4.20 is the smarter business decision.

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Model Specs

GPT-5.6 Sol

Website

Benchmarks & Scores

Coding (swe-bench-pro)Winner (+12.8%)

64.6%

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)Winner (+4.6%)

94.6%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)

$11.25Input: $5.00 | Output: $30.00

Context WindowLarger

1.05M tokens

Model Specs

Grok 4.20

Website

Benchmarks & Scores

Coding (swe-bench-pro)

51.8%

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)

90%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)3.8x cheaper

$3.00Input: $2.00 | Output: $6.00

Context Window

1.05M tokens

Read our data collection methodology

Frequently Asked Questions about GPT-5.6 Sol vs Grok 4.20

Grok 4.20 is cheaper than GPT-5.6 Sol. Grok 4.20 has a blended cost of $3.00/1M tokens, which is about 3.8x cheaper than GPT-5.6 Sol at $11.25/1M tokens.

GPT-5.6 Sol is better for coding tasks on this benchmark. It scores 64.6% on swe-bench-pro (excellent at multi-file repositories, autonomous agents, and industrial codebases) compared to Grok 4.20 which scores 51.8%.

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