GPT-5.6 Terra vs Hy4 preview: Specs & Benchmark Comparison
GPT-5.6 Terra is developed by OpenAI, while Hy4 preview comes from Tencent. GPT-5.6 Terra was released in July 2026, and Hy4 preview followed a month later in August 2026. Hy4 preview has a published size of about 770 billion parameters; OpenAI has not disclosed the parameter count of GPT-5.6 Terra.
The two models share 7 published benchmarks. GPT-5.6 Terra leads on 4 of them, Hy4 preview on 3. The widest gaps are on Agents' Last Exam, where GPT-5.6 Terra scores 50.4% against 22.8%; Toolathlon, where Hy4 preview scores 74.1% against 53.1%. Averaged across everything we track, GPT-5.6 Terra sits at 59.0% and Hy4 preview at 58.7%.
GPT-5.6 Terra is available through an API at $2 per million input tokens with a 1M-token context window. We do not track a hosted API for Hy4 preview, so pricing and context cannot be compared directly.
| Characteristic | GPT-5.6 Terra | Hy4 preview |
|---|---|---|
| Company | OpenAI | Tencent |
| Release Date | July 9, 2026 | August 28, 2026 |
| Parameters | — | 770B |
| Multimodal | Yes | No |
| Context (input) | 1.1M | — |
| Context (output) | 128K | — |
| Input Price / 1M | $2.00 | — |
| Output Price / 1M | $12.00 | — |
| Average Score | 59.0% | 58.7% |
| Benchmarks | ||
| Agents' Last Exam | 50.4% | 22.8% |
| Toolathlon | 53.1% | 74.1% |
| AutomationBench | 15.2% | 32.1% |
| DeepSWE | 69.6% | 64.3% |
| SWE-Bench Pro | 63.4% | 65.7% |
| Terminal-Bench 2.1 | 87.4% | 85.4% |
| GPQA | 92.9% | 92.3% |
Visual Benchmark Comparison
Verdict
Hy4 preview leads in 1 out of 2 comparison categories.
Both models show comparable average scores: GPT-5.6 Terra — 0.6, Hy4 preview — 0.6.
Hy4 preview is newer: released 8/28/2026 vs 7/9/2026.
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Frequently Asked Questions
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The GPT-5.6 Terra and Hy4 preview comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-5.6 Terra or Hy4 preview page. See also the complete list of AI model comparisons.