deepseek-v4-flash vs gpt-oss-120b

Capability for the money

deepseek-v4-flash is 2.6× cheaper than gpt-oss-120b and scores higher on hard reasoning (GPQA Diamond) — there is no case for paying more here.

1. Hard reasoning

   graduate-level science and multi-step analysis

   GPQA Diamond
   deepseek-v4-flash90.8%

   gpt-oss-120b78.2%

   deepseek-v4-flash +12.6

Averaged over the benchmarks both models sat, deepseek-v4-flash returns 518.9 points of pass rate per dollar of blended price against 173.8 — the ratio that decides whether the dearer model earns its rate.

Each figure is a pass rate: the share of that test set the model answered correctly, measured by a third party rather than self-reported by the lab. Rows are different tests of different difficulty, so compare a model against the other model, not one row against the next. No published following instructions, coding or tool use score for one of these models, so those lenses are omitted. And a benchmark is not your workload — it narrows the shortlist, it does not pick for you.