DeepSeek V4 Pro is a reasoning-tuned model that costs ~10x less than GPT-5 per token and frequently matches or beats it on hard problems. Settle the comparison on your prompt: CouncilMind runs both in parallel and shows you the reasoning trace.
GPT-5: The cleanest path is to factor this into recursive subproblems; complexity is O(n log n).
DeepSeek V4 Pro [reasoning]: We must verify the recursion hypothesis. Base case: ... Step: ... Conclusion: O(n log n) is correct, but only if the partition is balanced—worst case O(n²).
Verdict: DeepSeek caught the worst-case GPT-5 implied. On hard reasoning, the cheaper model often wins on rigor.
The price gap is huge. The capability gap, often, isn't.
DeepSeek V4 Pro shows its work. GPT-5 doesn't. You see where each one's confidence comes from.
No isolated benchmarks. Your actual question, both actual models.
The judge weighs answer quality and effective cost—the right model for your real workflow.
Hard reasoning is where the gap closes
Math, logic, debugging, multi-step reasoning—the harder the better.
GPT-5 answers; DeepSeek V4 Pro shows its full reasoning trace.
A third model explains which reasoning held up under scrutiny.
Free tier includes both. No credit card.