Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
DeepSeekMath V2 and Step 3.5 Flash finish on the same overall score, so this is less about a single winner and more about where the edge shows up. The headline says tie; the benchmark table is where the real choice happens.
DeepSeekMath V2 is the reasoning model in the pair, while Step 3.5 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. Step 3.5 Flash gives you the larger context window at 256K, compared with 128K for DeepSeekMath V2.
Treat this as a split decision. DeepSeekMath V2 makes more sense if agentic is the priority or you want the stronger reasoning-first profile; Step 3.5 Flash is the better fit if instruction following is the priority or you need the larger 256K context window.
DeepSeekMath V2
63.9
Step 3.5 Flash
60.2
DeepSeekMath V2
47.3
Step 3.5 Flash
47.1
DeepSeekMath V2
68.1
Step 3.5 Flash
66.7
DeepSeekMath V2
75.9
Step 3.5 Flash
78.3
DeepSeekMath V2
61
Step 3.5 Flash
60.8
DeepSeekMath V2
83
Step 3.5 Flash
87
DeepSeekMath V2
82.5
Step 3.5 Flash
82.8
DeepSeekMath V2
84
Step 3.5 Flash
84.5
DeepSeekMath V2 and Step 3.5 Flash are tied on overall score, so the right pick depends on which category matters most for your use case.
DeepSeekMath V2 has the edge for knowledge tasks in this comparison, averaging 61 versus 60.8. Inside this category, HLE is the benchmark that creates the most daylight between them.
DeepSeekMath V2 has the edge for coding in this comparison, averaging 47.3 versus 47.1. Inside this category, HumanEval is the benchmark that creates the most daylight between them.
Step 3.5 Flash has the edge for math in this comparison, averaging 84.5 versus 84. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.
Step 3.5 Flash has the edge for reasoning in this comparison, averaging 78.3 versus 75.9. Inside this category, MuSR is the benchmark that creates the most daylight between them.
DeepSeekMath V2 has the edge for agentic tasks in this comparison, averaging 63.9 versus 60.2. Inside this category, OSWorld-Verified is the benchmark that creates the most daylight between them.
DeepSeekMath V2 has the edge for multimodal and grounded tasks in this comparison, averaging 68.1 versus 66.7. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.
Step 3.5 Flash has the edge for instruction following in this comparison, averaging 87 versus 83. Inside this category, IFEval is the benchmark that creates the most daylight between them.
Step 3.5 Flash has the edge for multilingual tasks in this comparison, averaging 82.8 versus 82.5. Inside this category, MGSM is the benchmark that creates the most daylight between them.
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