Head-to-head comparison across 1benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
DeepSeek V4 Flash Base
31
GPT-5.5 Pro
100
Pick GPT-5.5 Pro if you want the stronger benchmark profile. DeepSeek V4 Flash Base only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.
Knowledge
+5.0 difference
DeepSeek V4 Flash Base
GPT-5.5 Pro
$null / $null
$30 / $180
N/A
N/A
N/A
N/A
1M
1M
Pick GPT-5.5 Pro if you want the stronger benchmark profile. DeepSeek V4 Flash Base only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.
GPT-5.5 Pro is clearly ahead on the provisional aggregate, 100 to 31. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.5 Pro's sharpest advantage is in knowledge, where it averages 57.2 against 52.2.
GPT-5.5 Pro is the reasoning model in the pair, while DeepSeek V4 Flash Base 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 Pro is ahead on BenchLM's provisional leaderboard, 100 to 31.
GPT-5.5 Pro has the edge for knowledge tasks in this comparison, averaging 57.2 versus 52.2. DeepSeek V4 Flash Base stays close enough that the answer can still flip depending on your workload.
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