GPT-5.5 vs DeepSeek V4 Pro
Side-by-side comparison across metrics, pricing, and overall score — every value traced to a source.
Verdict: GPT-5.5 ranks highest overall (#3) with a score of 52.5.
The best choice still depends on which metrics matter for your workload — per-metric winners are marked below.
What the numbers hide
Computed from the published values below — no estimates, no generated claims.
Fragile verdict
The overall winner flips to GPT-5.5 if SWE-Bench Pro Score is weighted at 35% (it counts for 29% today). If swe-bench pro score drives your decision, the ranking above may not be your ranking.
Fragile verdict
The overall winner flips to GPT-5.5 if Context Window is weighted at 25% (it counts for 18% today). If context window drives your decision, the ranking above may not be your ranking.
Real tradeoff
GPT-5.5 clearly beats DeepSeek V4 Pro on Context Window but clearly loses on Input Price — this pair is a priorities question, not a quality question.
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| Metric | GPT-5.5OpenAI | DeepSeek V4 ProDeepSeek |
|---|---|---|
| Overall OptiSift Score | 52.5#3 | 51.8#4 |
| Input Price | $5 | $0.44 |
| Output Price | $30 | $0.87 |
| Cache Read Price | $0.5 | $0 |
| Context Window | 1.1M | 1M |
| Max Output Tokens | 128K | 384K |
| SWE-Bench Pro Score | 58.6% | 18% |
| Tool Calling | Yes | Yes |
| Extended Reasoning | Yes | Yes |
About these models
#3GPT-5.5
OpenAI
GPT-5.5 is OpenAI's reasoning-capable model: $5/$30 per 1M input/output tokens, 1.1M token context window, 58.6% on SWE-Bench Pro.
#4DeepSeek V4 Pro
DeepSeek
DeepSeek V4 Pro is DeepSeek's reasoning-capable model: $0.43/$0.87 per 1M input/output tokens, 1M token context window, 18% on SWE-Bench Pro.