Claude Opus 4.6 vs Gemini 3.8 Flash
Vals Science Index?
Opus 4.6—
Gemini 3.8 Flash35.8
| Benchmark | Opus 4.6 | Gemini 3.8 Flash |
|---|---|---|
| Humanity's Last Exam | 19.1 | 42.1 |
| Arena Text · overall | 1,503 | 1,496 · high |
| Arena Text · Chinese | 1,551 | 1,552.5 · high |
| Arena Text · English | 1,511.3 | 1,498.4 · high |
| Arena Text · French | 1,511.9 | 1,494.8 · high |
| Arena Text · German | 1,501.9 | 1,509.2 · high |
| Arena Text · instruction following | 1,521 | 1,491.6 · high |
| Arena Text · Japanese | 1,488 | 1,511.3 · high |
| Arena Text · Korean | 1,448.8 | 1,471.1 · high |
| Arena Text · non-English | 1,487.6 | 1,490.9 · high |
| Arena Text · Polish | 1,497.2 | 1,496.1 · high |
| Arena Text · Russian | 1,495.3 | 1,515.8 · high |
| Arena Text · Spanish | 1,503.5 | 1,485 · high |
| AA Omniscience Index | 2.4 | 28.6 |
| SimpleQA Verified v1 | 47 · max | 74.6 |
| CritPt (physics) | 2.8 | 12.3 |
| AA Intelligence Index 4.3.2 | 26.4 | 39.8 |
| AA Omniscience · Accuracy | 45.8 | 53 |
| AA Omniscience · Hallucination Rate | 80.1 | 51.9 |
| AA-LCR (long context) 1.1 | 67 | 84 |
| ARC-AGI-1 · public evaluation | 96.3 | 97.8 |
| ARC-AGI-1 · semi-private | 94 | 97.5 |
| ARC-AGI-2 · public evaluation | 79 | 87.5 |
| ARC-AGI-2 · semi-private | 69.2 | 82.9 |
| Chess Puzzles | 21 · max | 58 · high |
| FrontierMath Tier 4 (v2) | 26.8 · max | 22 · high |
| FrontierMath Tiers 1–3 (v2) | 66 · max | 68.4 · high |
| Mystery Game Puzzles | 25 · max | 47 · high |
| Vals LegalBench | 85.3 | 87 |
| Vals MedCode | 49.1 | 48.1 |
| Vals MedScribe | 86.1 | 84.5 |
| GDP.pdf · AA all-pass | — | 22.8 |
| IFBench (instructions) | 44.6 | — |
| MLCR-AA | — | 12.8 |
| ARC-AGI-3 · semi-private | — | 4 |
| EQ-Bench 3 | 1,712.4 | — |
| FrontierMath | 40.7 · max | — |
| FrontierMath Erdos | — | 0 · high |
| FrontierMath Tier 4 | 22.9 · max | — |
| MathArena · Apex | 34.5 | — |
| MathArena · Apex Shortlist | 86.7 | — |
| MathArena · ArXivMath · April 2026 | — | 64.2 |
| MathArena · ArXivMath · August 2026 | — | 40.4 |
| MathArena · ArXivMath · December 2025 | 57.4 | — |
| MathArena · ArXivMath · February 2026 | 40.6 | — |
| MathArena · ArXivMath · January 2026 | 72.8 | — |
| MathArena · ArXivMath · June 2026 | — | 67.4 |
| MathArena · ArXivMath · March 2026 | 62.5 | — |
| MathArena · ArXivMath · May 2026 | — | 58.3 |
| MathArena · ArXivMath · September 2026 | — | 50 |
| MathArena · BrokenArXiv · April 2026 | — | 33.6 |
| MathArena · BrokenArXiv · August 2026 | — | 27.4 |
| MathArena · BrokenArXiv · February 2026 | 3.2 | — |
| MathArena · BrokenArXiv · June 2026 | — | 20.8 |
| MathArena · BrokenArXiv · March 2026 | 5.8 | — |
| MathArena · BrokenArXiv · May 2026 | — | 19 |
| MathArena · BrokenArXiv · September 2026 | — | 26.7 |
| MathArena · ArXivLean · June 2026 | — | 19.6 |
| MathArena · Project Euler | 87.7 | — |
| MathArena · Kangaroo 2025 1-2 | 59.4 | — |
| MathArena · Kangaroo 2025 11-12 | 87.5 | — |
| MathArena · Kangaroo 2025 3-4 | 50 | — |
| MathArena · Kangaroo 2025 5-6 | 58.3 | — |
| MathArena · Kangaroo 2025 7-8 | 86.7 | — |
| MathArena · Kangaroo 2025 9-10 | 91.7 | — |
| MathArena · USAMO 2026 | 47 | — |
| Vals Legal Research Bench | — | 38.9 |
| Vals Science Index | — | 35.8 |
Specs
| Spec | Opus 4.6 | Gemini 3.8 Flash |
|---|---|---|
| Input, per 1M | $5 | !$0.75 |
| Output, per 1M | $25 | !$3.75 |
| Cost per task? | — | $0.93 |
| Speed, tok/s | 43 | — |
| Context | 1M | 1M |
| Weights | Closed | Closed |
| Released | Feb 2026 | Sep 2026 |
| See images | ✓ | ✓ |
| Read PDFs | Partial | ✓ |
| Hear audio | — | ✓ |
| Watch video | — | ✓ |
| Call tools | ✓ | ✓ |
| Force a tool call | Partial | Partial |
| Return strict JSON | ✓ | ✓ |
| Search the web | ? | ✓ |
| Run code | ? | ✓ |
| Use a computer | ? | ? |
What breaks when you switch
Opus 4.6 → Gemini 3.8 Flash
Sampling parameters are ignored›
temperature, top_p and top_k are ignored now and will cause HTTP 400 in future generations; remove them from requests.
No minimal thinking level›
The minimal thinking level returns an error; avoid minimal.
Gemini 3.8 Flash → Opus 4.6
Nothing known.