Claude Opus 4.6 vs GPT-5.1

Choose Claude Opus 4.6 if you want…

• ✓Larger context window (1M)

Choose GPT-5.1 if you want…

• ✓Higher intelligence (Artificial Analysis index 48)
• ✓Faster output (~142.7 tokens/sec)
• ✓Lower price ($3.44 / 1M blended)

Claude Opus 4.6

Opus 4.6 is the model researchers and engineers reach for when the problem genuinely cannot be chunked — loading an entire codebase, a year's worth of literature, or a complex multi-part investigation into a single session of up to 750,000 words. It tops Terminal-Bench 2.0 among frontier models for agentic coding tasks and leads BrowseComp for hard-to-locate information retrieval, reflecting a design philosophy built around sustained, autonomous work rather than quick exchanges. Scientists have noted roughly double the accuracy on computational biology and structural chemistry tasks versus its predecessor. The tradeoff is speed: at 38.8 tokens per second, it feels noticeably slower than alternatives during interactive back-and-forth. The 1M-token window is also still in beta, and users report meaningful performance degradation well before hitting its ceiling. Best suited to high-stakes tasks where depth matters more than pace.

GPT-5.1

GPT-5.1 earns its place through adaptive reasoning — a system that genuinely calibrates effort to the task, running roughly twice as fast on straightforward queries and digging deeper on complex ones. That mechanical intelligence shows up in the benchmarks: 94% on AIME 2025, 88.1% on GPQA Diamond, and a 76.3% solve rate on SWE-Bench Verified, making it one of the more capable off-the-shelf options for serious coding and research-level math. Users consistently praise how much cleaner the code output is — fewer logic errors, better edge-case handling — and the improved tool-calling reliability makes it a practical choice for production agentic pipelines. The catch is that the Auto-routing variant has frustrated users who found it silently redirecting requests through stricter safety filters without explanation, a criticism that turned OpenAI's own Reddit launch AMA into a notable PR setback. For teams willing to pick the right variant (Instant, Thinking, or Auto) and work within a September 2024 knowledge cutoff, GPT-5.1 offers strong price-to-capability value at $1.25 per million input tokens — cheaper than its GPT-5.2 successor while covering most production needs.