Gemini 3.8 Flash · Comparison

Gemini 3.8 Flash vs Claude Opus 5: where each wins

On long-horizon agent work, open-ended computer use and broad professional tasks, Opus 5 wins by a wide margin. On finance, legal and long video, Gemini 3.8 Flash wins at a fraction of the per-token cost.

Dated comparison: 3 September 2026

MetricGemini 3.8 FlashClaude Opus 5
AA Intelligence Index5963
Terminal-Bench 2.189.4%89.1%
Terminal-Bench 4.019.1%51.8%
OSWorld 2.059.0%75.4%
GDPval-AA v21545 Elo1824 Elo
Vals Finance Agent v261.4%58.6%
Harvey Legal Agent10.0%6.7%
LVBench (agentic)87.8%75.4%
HLE-Verified54.9%54.4%
DeepSWE v1.173.7%74.0%
Standard input / 1M$0.75~$5
Standard output / 1M$3.75~$30
Time to first token13.39 sLower
WeightsClosedClosed

How to choose

Pick Gemini 3.8 Flash for finance agents, legal document review, long video, batch processing and cost-bound coding tasks. Pick Opus 5 for open-ended long-horizon agents, computer use and broad professional work. The four losses above 15 points are the place Gemini's head-to-head positioning is weakest.

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Comparison limits

These figures are transcribed from the 3 September 2026 research snapshot. Opus 5's per-token prices are approximate ranges reported by third-party aggregators; verify against your billing portal before quoting.

Frequently asked questions

How current is this information?

This page uses the verified research snapshot dated 3 September 2026. Verify current access, pricing and benchmark figures before a production decision.

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