GPT-5.6 Terra vs Grok 4.5
Head-to-head specifications
| Metric | GPT-5.6 Terra | Grok 4.5 | Difference |
|---|---|---|---|
| Intelligence Index | 55.0 | 54.0 | +1.9% |
| Coding Index | 76.7 | 72.4 | +5.9% |
| Agentic Index | 47.4 | 45.7 | — |
| Context window | 1M tokens | 922K tokens | — |
| Blended price ($/1M tokens) | $1.14 | $0.87 | +31.0% |
| Output speed (tokens/s) | 138 | 118 | +16.9% |
| Access | Proprietary API | Proprietary API | — |
- GPT-5.6 Terra leads overall capability (Intelligence Index 55.0 vs 54.0).
- Grok 4.5 is the cheaper model to run at $0.87/1M blended tokens — about 1.3× cheaper.
- GPT-5.6 Terra offers the larger context window (1M tokens), useful for long documents and codebases.
Verdict: GPT-5.6 Terra or Grok 4.5?
GPT-5.6 Terra advantages
- Coding ability (+6%)
- Context window (+8%)
- Output speed (+14%)
Grok 4.5 advantages
- Affordability (+24%)
Which should you choose?
- Choose the GPT-5.6 Terra if coding and software development are your main workload.
- Choose the Grok 4.5 if you want the lowest cost per token at scale.
- Choose the GPT-5.6 Terra if you work with long documents or large codebases.
Value for money
Grok 4.5 offers more intelligence per dollar (1.3× the Intelligence-Index-per-cost of the alternative), making it the stronger value for high-volume use.
GPT-5.6 Terra vs Grok 4.5: which should you choose?
GPT-5.6 Terra — OpenAI multimodal model with an Intelligence Index of 55, a 1M-token context window and a blended price of $1.14/1M tokens.
Grok 4.5 — xAI multimodal model with an Intelligence Index of 54, a 922K-token context window and a blended price of $0.87/1M tokens.
GPT-5.6 Terra vs Grok 4.5: GPT-5.6 Terra scores higher on the Intelligence Index. GPT-5.6 Terra leads overall capability (Intelligence Index 55.0 vs 54.0). Grok 4.5 is the cheaper model to run at $0.87/1M blended tokens — about 1.3× cheaper.
Capability: intelligence, coding and agentic work
On the composite Intelligence Index the GPT-5.6 Terra scores 55.0 versus 54.0. For software development, the Coding Index puts GPT-5.6 Terra ahead (76.7 vs 72.4). On agentic, multi-step tool-use tasks, GPT-5.6 Terra measures stronger. Composite indices summarize many evaluations, but always test on your own workload before committing.
Context window and speed
The GPT-5.6 Terra accepts up to 1 million tokens per request, which sets how much documentation, transcript or code it can reason over at once. In measured throughput, GPT-5.6 Terra generates faster (138 vs 118 tokens/s), which matters for interactive apps and high-volume pipelines.
Pricing and access
At blended per-token rates, Grok 4.5 is the cheaper model to run ($0.87 vs $1.14 per 1M tokens). GPT-5.6 Terra is proprietary api and Grok 4.5 is proprietary api. Open-weight models can be self-hosted, trading per-call cost for infrastructure you manage; for production also weigh rate limits, throughput and data-residency requirements.
The verdict
Both are credible choices in the ai model comparison space; the specification table above lays out every metric so you can weigh the trade-offs that matter to you. Pick the one whose strengths line up with how you will actually use it.
Frequently asked questions
Is the GPT-5.6 Terra better than the Grok 4.5?
GPT-5.6 Terra takes the overall edge, though Grok 4.5 wins in specific areas worth weighing. GPT-5.6 Terra leads overall capability (Intelligence Index 55.0 vs 54.0).
What is the main difference between the GPT-5.6 Terra and the Grok 4.5?
GPT-5.6 Terra leads overall capability (Intelligence Index 55.0 vs 54.0). Grok 4.5 is the cheaper model to run at $0.87/1M blended tokens — about 1.3× cheaper.
Which is better value?
Grok 4.5 offers more intelligence per dollar (1.3× the Intelligence-Index-per-cost of the alternative), making it the stronger value for high-volume use.
Which should I choose?
Choose the GPT-5.6 Terra if coding and software development are your main workload. Choose the Grok 4.5 if you want the lowest cost per token at scale.
Methodology
Large language models are compared on independent leaderboard metrics: an Intelligence Index (a composite of reasoning and knowledge evaluations), Coding and Agentic indices where measured, community arena Elo, maximum context window, a blended API price per million tokens (weighted across cache-hit, input and output rates), and measured output speed in tokens per second. Where a model ships multiple reasoning-effort variants, we report its strongest variant. Benchmarks capture only part of real-world quality, which also depends on tool use, latency, safety and task fit — and this space moves quickly, so figures reflect the leaderboard snapshot on the page date.