Three frontier AI models. Three different philosophies. One question: which one should you actually use?
GPT-5.5, Claude Opus 4.7, and Gemini 3.1 Pro Preview represent the cutting edge of AI in July 2026. But their strengths are wildly different. This head-to-head comparison uses real benchmark data to help you pick the right model for your work.
TL;DR Verdict
- Coding: Claude Opus 4.7 wins (83.5% SWE-bench)
- Math: GPT-5.5 Pro wins (87.7% FrontierMath, 100% OTIS AIME)
- Science: GPT-5.5 wins (94.0% GPQA Diamond)
- Reasoning: Claude Fable 5 wins (81.9% SimpleBench) — different tier but worth noting
- Value: Gemini 3.5 Flash wins (79.3% SWE-bench at Flash pricing)
- Long tasks: Claude family wins (Mythos Preview at 17+ hours)
Coding: SWE-bench Verified
Real GitHub issues. Real unit tests. No room for hallucinated solutions.
| Model | SWE-bench Verified | Terminal-Bench | GSO (Optimization) |
|---|---|---|---|
| Claude Opus 4.7 (max) | 83.5% | 90.2% | 44.1% |
| GPT-5.5 (xhigh) | 80.6% | 85.1% | 40.2% |
| Gemini 3.1 Pro Preview | 74.8% | 78.3% | 28.7% |
Claude Opus 4.7 is the clear coding champion. It leads on every coding benchmark, with particularly dominant performance on Terminal-Bench (command-line tasks) and GSO (code optimization — making existing code faster).
GPT-5.5 is close behind on SWE-bench but falls behind on optimization tasks. Gemini 3.1 Pro is solid but clearly third place for pure code.
Winner: Claude Opus 4.7
Mathematics: FrontierMath v2 & OTIS
| Model | FrontierMath Tiers 1-3 | OTIS Mock AIME |
|---|---|---|
| GPT-5.5 Pro (xhigh) | 87.7% | 100.0% |
| GPT-5.5 (xhigh) | 85.2% | 98.4% |
| Gemini 3.1 Pro Preview | 82.1% | 95.7% |
| Claude Opus 4.7 | 78.9% | 93.2% |
GPT-5.5 Pro is in a league of its own for mathematics. A perfect score on OTIS Mock AIME — a competition math benchmark — is staggering. If you work in quantitative finance, cryptography, physics, or any math-heavy field, GPT-5.5 Pro is the obvious choice.
Claude Opus 4.7 is no slouch but trails by 7-9 points on FrontierMath.
Winner: GPT-5.5 Pro
Science & Knowledge: GPQA Diamond
| Model | GPQA Diamond |
|---|---|
| GPT-5.5 (xhigh) | 94.0% |
| Gemini 3.1 Pro Preview | 94.1% |
| Claude Opus 4.7 | 91.8% |
Nearly tied at the top. GPT-5.5 and Gemini 3.1 Pro are both exceptional on PhD-level science questions. Claude Opus 4.7 is slightly behind but still excellent.
Winner: Tie (GPT-5.5 / Gemini 3.1 Pro)
Reasoning: SimpleBench
| Model | SimpleBench |
|---|---|
| Gemini 3.1 Pro Preview | 79.6% |
| GPT-5.5 Pro | 76.9% |
| Claude Opus 4.7 | 74.8% |
SimpleBench tests whether models can avoid common-sense reasoning traps. Gemini 3.1 Pro Preview takes this one, edging out GPT-5.5 Pro. Claude Fable 5 (a different Anthropic tier) actually leads this benchmark at 81.9%, but it's not a direct competitor at the Opus tier.
Winner: Gemini 3.1 Pro Preview
Long-Context and Endurance
| Model | METR Time Horizon | Fiction.liveBench |
|---|---|---|
| Claude Opus 4.6 | 718.8 min (~12 hrs) | 88.2% |
| GPT-5.5 | 352.2 min (~5.9 hrs) | 93.1% |
| Gemini 3.1 Pro Preview | 384.1 min (~6.4 hrs) | 85.7% |
Claude models are built for endurance. The Opus line can work autonomously for half a day. But for pure long-context comprehension (Fiction.liveBench), GPT-5.5 actually scores higher.
Winner: Claude (endurance) / GPT-5.5 (comprehension)
Pricing Showdown
| Model | Input/1M | Output/1M | Context |
|---|---|---|---|
| Claude Opus 4.7 | $15 | $75 | 500K |
| GPT-5.5 Pro | $12 | $60 | 400K |
| GPT-5.5 | $5 | $20 | 400K |
| Gemini 3.1 Pro | $7 | $21 | 2M |
Gemini 3.1 Pro has a massive advantage here: 2M context window at roughly half the price of Claude Opus. For processing long documents, codebases, or research papers, Gemini offers the best price-to-performance ratio.
GPT-5.5 (standard, not Pro) at $5/$20 is the value pick of the GPT lineup — you get FrontierMath-leading math performance at quarter the Pro price.
When to Pick Which
Choose Claude Opus 4.7 if:
- You write or debug code daily
- You need long autonomous coding sessions
- Code optimization matters (GSO benchmark)
- Budget is not the primary concern
Choose GPT-5.5 Pro if:
- You work with math, science, or quantitative analysis
- You need top-tier reasoning across many domains
- Competition-level math performance matters
- You want the best "knowledge worker" model (GDPval)
Choose Gemini 3.1 Pro if:
- You process very long documents (2M context)
- You want strong all-around performance at lower cost
- You're integrated with Google's ecosystem
- You need excellent common-sense reasoning
The Dark Horse: Open-Weight Alternatives
Don't want to depend on API providers? DeepSeek V4 and Qwen 3.5 offer frontier-level performance as open weights. You can self-host them, fine-tune them, and run them with complete privacy.
For developers who want offline AI without server management, the PortableMind USB ships pre-loaded with top open-weight models — no GPU, no cloud, no setup.
Final Scorecard
| Category | Winner | Margin |
|---|---|---|
| Coding | Claude Opus 4.7 | +2.9% on SWE-bench |
| Math | GPT-5.5 Pro | +2.5% on FrontierMath |
| Science | GPT-5.5 / Gemini 3.1 | Within 0.1% |
| Reasoning | Gemini 3.1 Pro | +2.7% on SimpleBench |
| Long tasks | Claude Opus | 2x METR horizon |
| Value | Gemini 3.1 Pro | 2M context, lower price |
| Open-weight | DeepSeek V4 | Closest to frontier |
There's no single "best" model. The frontier is specialized now. Pick the one that matches your workload.