DeepSeekDeepSeek V4 FlashVSOpenAIGPT-5.5
Our Take
We recommend GPT-5.5 if you need peak intelligence for reasoning and coding tasks, or the 64.3x cheaper DeepSeek V4 Flash to optimize your budget for high-volume pipelines. While GPT-5.5 holds a clear performance lead, it carries a heavy price premium. Choose GPT-5.5 for complex logic, or DeepSeek V4 Flash for budget efficiency.
▶WHY?
Benchmark Calculations & Evidence:
Coding Benchmarks: Both models were evaluated on the SWE-bench Pro benchmark. GPT-5.5 scored 58.6%, while DeepSeek V4 Flash scored 49.1%.
Reasoning Benchmarks: Both models were evaluated on the GPQA Diamond benchmark. GPT-5.5 scored 93.6%, while DeepSeek V4 Flash scored 80%.
Cost Efficiency: DeepSeek V4 Flash pricing ($0.14/M input, $0.28/M output) is 64.3x cheaper than GPT-5.5 ($5/M input, $30/M output).
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Benchmarks & Scores
Coding (swe-bench-pro)
49.1%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)
80%graduate-level science QA
Cost & Context
Cost (per 1M tokens)64.3x cheaper
$0.17Input: $0.14 | Output: $0.28Context Window
1.05M tokensBenchmarks & Scores
Coding (swe-bench-pro)Winner (+9.5%)
58.6%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)Winner (+13.6%)
93.6%graduate-level science QA
Cost & Context
Cost (per 1M tokens)
$11.25Input: $5.00 | Output: $30.00Context WindowLarger
1.05M tokensFrequently Asked Questions about DeepSeek V4 Flash vs GPT-5.5
DeepSeek V4 Flash is cheaper than GPT-5.5. DeepSeek V4 Flash has a blended cost of $0.17/1M tokens, which is about 64.3x cheaper than GPT-5.5 at $11.25/1M tokens.
GPT-5.5 is better for coding tasks on this benchmark. It scores 58.6% on swe-bench-pro (complex codebases, multi-file repositories, and architectural planning) compared to DeepSeek V4 Flash which scores 49.1%.
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