Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
Seed 1.6 Flash is clearly ahead on the aggregate, 56 to 45. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Seed 1.6 Flash's sharpest advantage is in multilingual, where it averages 72.8 against 48. The single biggest benchmark swing on the page is MMLU-ProX, 71 to 48. GPT-5 nano does hit back in mathematics, so the answer changes if that is the part of the workload you care about most.
GPT-5 nano is also the more expensive model on tokens at $0.05 input / $0.40 output per 1M tokens, versus $0.08 input / $0.30 output per 1M tokens for Seed 1.6 Flash. GPT-5 nano gives you the larger context window at 400K, compared with 256K for Seed 1.6 Flash.
Pick Seed 1.6 Flash if you want the stronger benchmark profile. GPT-5 nano only becomes the better choice if mathematics is the priority or you need the larger 400K context window.
Seed 1.6 Flash
54.5
GPT-5 nano
37.7
Seed 1.6 Flash
27.6
GPT-5 nano
22
Seed 1.6 Flash
73.1
GPT-5 nano
56.7
Seed 1.6 Flash
66.8
GPT-5 nano
58.8
Seed 1.6 Flash
47.3
GPT-5 nano
63.7
Comparable scores for this category are coming soon. One or both models do not have sourced results here yet.
Seed 1.6 Flash
72.8
GPT-5 nano
48
Seed 1.6 Flash
67.1
GPT-5 nano
85.2
Seed 1.6 Flash is ahead overall, 56 to 45. The biggest single separator in this matchup is MMLU-ProX, where the scores are 71 and 48.
GPT-5 nano has the edge for knowledge tasks in this comparison, averaging 63.7 versus 47.3. Inside this category, GPQA is the benchmark that creates the most daylight between them.
Seed 1.6 Flash has the edge for coding in this comparison, averaging 27.6 versus 22. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
GPT-5 nano has the edge for math in this comparison, averaging 85.2 versus 67.1. Inside this category, AIME 2025 is the benchmark that creates the most daylight between them.
Seed 1.6 Flash has the edge for reasoning in this comparison, averaging 66.8 versus 58.8. Inside this category, LongBench v2 is the benchmark that creates the most daylight between them.
Seed 1.6 Flash has the edge for agentic tasks in this comparison, averaging 54.5 versus 37.7. Inside this category, OSWorld-Verified is the benchmark that creates the most daylight between them.
Seed 1.6 Flash has the edge for multimodal and grounded tasks in this comparison, averaging 73.1 versus 56.7. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.
Seed 1.6 Flash has the edge for multilingual tasks in this comparison, averaging 72.8 versus 48. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.
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