DeepSeek-V3 vs GPT-5.5 Pro
Verdict
GPT-5.5 Pro leads 4–0 across 4 shared benchmarks.
DeepSeek-V3 0 · GPT-5.5 Pro 4 · higher isn't always better — see caveats.
Per-benchmark head-to-head
Reported scores — protocols may differ. How we compare
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DeepSeek-V3GPT-5.5 Pro
Capabilities
Reasoning
Reasoning: GPT-5.5 Pro leads 2–0 across 2 shared reasoning benchmarks (largest gap: SimpleBench, 72.28 vs 2.68 — single evaluator).
2 reproduced2 unverified
What the labs claim
Vendor claims — compare against the measured scores above. A claim is what a developer says about its own model, not an independent measurement.
DeepSeek-V3
Coding
“DeepSeek-V3 achieves the best performance on most benchmarks, especially on math and code tasks.”
github.com2024
General
“At an economical cost of only 2.664M H800 GPU hours, we complete the pre-training of DeepSeek-V3 on 14.8T tokens, producing the currently strongest open-source base model.”
github.com2024“DeepSeek-V3 outperforms other open-source models and achieves performance comparable to leading closed-source models.”
github.com2024
Reasoning
“Our pipeline elegantly incorporates the verification and reflection patterns of R1 into DeepSeek-V3 and notably improves its reasoning performance.”
github.com2024
GPT-5.5 Pro
General
“In GPT-5.5 Pro, early testers are seeing a significant step up in both the difficulty and quality of work ChatGPT can take on”
openai.com2026
Reasoning
“GPT-5.5 Pro, designed for even harder questions and higher-accuracy work, is available to Pro, Business, and Enterprise users.”
openai.com2026
Writing
“testers found GPT-5.5 Pro's responses significantly more comprehensive, well-structured, accurate, relevant, and useful”
openai.com2026