DeepSeek V3 vs GPT-5.5

Pick GPT-5.5 if you want the stronger benchmark profile. DeepSeek V3 only becomes the better choice if knowledge is the priority or you want the cheaper token bill.

GPT-5.5 is clearly ahead on the provisional aggregate, 91 to 35. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.5's sharpest advantage is in coding, where it averages 58.6 against 39.2. The single biggest benchmark swing on the page is GPQA, 59.1% to 93.6%. DeepSeek V3 does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.

GPT-5.5 is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $0.27 input / $1.10 output per 1M tokens for DeepSeek V3. That is roughly 27.3x on output cost alone. GPT-5.5 is the reasoning model in the pair, while DeepSeek V3 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. GPT-5.5 gives you the larger context window at 1M, compared with 128K for DeepSeek V3.