gemini-3.5-flash vs gpt-oss-120b

Capability for the money

Not the same tier: gemini-3.5-flash leads gpt-oss-120b by 29.5 points on tool use (τ²-bench), for 7.5× the price.

1. Following instructions

   extraction, classification, sticking to a format

   IFBench
   gemini-3.5-flash76.3%

   gpt-oss-120b69.0%

   gemini-3.5-flash +7.3

2. Tool use

   multi-step agent work against real tools

   τ²-bench
   gemini-3.5-flash95.3%

   gpt-oss-120b65.8%

   gemini-3.5-flash +29.5

3. Hard reasoning

   graduate-level science and multi-step analysis

   GPQA Diamond
   gemini-3.5-flash92.2%

   gpt-oss-120b78.2%

   gemini-3.5-flash +14.0

Averaged over the benchmarks both models sat, gpt-oss-120b returns 157.8 points of pass rate per dollar of blended price against 26.1 — 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 coding score for one of these models, so that lens is omitted. And a benchmark is not your workload — it narrows the shortlist, it does not pick for you.