GPT-5 Pro vs Solar Pro 3

Compare GPT-5 Pro by OpenAI against Solar Pro 3 by Upstage, context windows of 400K vs 128K, tested across 32 shared challenges. Updated April 2026.

Which is better, GPT-5 Pro or Solar Pro 3?

GPT-5 Pro and Solar Pro 3 are both competitive models. GPT-5 Pro costs $15/M input tokens vs $0/M for Solar Pro 3. Context windows: 400K vs 128K tokens. Compare their real outputs side by side below.

Key Differences Between GPT-5 Pro and Solar Pro 3

GPT-5 Pro is made by openai while Solar Pro 3 is from upstage. GPT-5 Pro has a 400K token context window compared to Solar Pro 3's 128K. On pricing, GPT-5 Pro costs $15/M input tokens vs $0/M for Solar Pro 3.

Our Verdict
GPT-5 Pro
GPT-5 Pro
Solar Pro 3
Solar Pro 3Runner-up

No community votes yet. On paper, GPT-5 Pro has the edge — bigger model tier, bigger context window, major provider backing.

Too close to call
Writing DNA

Style Comparison

Similarity
95%

Solar Pro 3 uses 654.8x more bold

GPT-5 Pro
Solar Pro 3
65%Vocabulary50%
15wSentence Length21w
0.32Hedging0.42
0.0Bold6.5
2.9Lists2.2
0.00Emoji0.17
0.00Headings0.56
0.01Transitions0.12
Based on 11 + 18 text responses
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GPT-5 ProSolar Pro 3

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
Free preview13 of 58 slides
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