DeepSeek V4 Flash vs GPT-5.4

Pick GPT-5.4 if you want the stronger benchmark profile. DeepSeek V4 Flash only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

GPT-5.4 is clearly ahead on the provisional aggregate, 88 to 59. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.4's sharpest advantage is in agentic, where it averages 77 against 49.1. The single biggest benchmark swing on the page is HLE, 8.1% to 52.1%.

GPT-5.4 is also the more expensive model on tokens at $2.50 input / $15.00 output per 1M tokens, versus $0.14 input / $0.28 output per 1M tokens for DeepSeek V4 Flash. That is roughly 53.6x on output cost alone. GPT-5.4 is the reasoning model in the pair, while DeepSeek V4 Flash 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-5.4 gives you the larger context window at 1.05M, compared with 1M for DeepSeek V4 Flash.