Model comparison
GPT-5.1-Codex vs Hy4 preview
Hy4 preview is the stronger model overall, scoring 45.3 to 38.6 on the Noometry Index.
Last verified . 2 shared benchmarks.
TencentSummary
- They share 2 benchmarks with published results for both. GPT-5.1-Codex scores higher in 0 categories and Hy4 preview in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in math, where Hy4 preview leads 55.7 to 30.3.
- The biggest single-benchmark swing is ProofBench: 9% for GPT-5.1-Codex and 75% for Hy4 preview.
- Hy4 preview is cheaper at $0.83 / $2.50 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
- Hy4 preview accepts more context: 1.05M tokens versus 400K.
- Hy4 preview has downloadable open weights; the other is API-only.
Side by side
| GPT-5.1-Codex | Hy4 preview | |
|---|---|---|
| Provider | OpenAI | Tencent |
| Noometry Index | 38.6 | 45.3 |
| Released | 2025-11-12 | 2026-08-28 |
| Weights | Proprietary | Open |
| Context window | 400K | 1.05M |
| Max output | 128K | 64K |
| Input $ / M tokens | $1.25 | $0.83 |
| Output $ / M tokens | $10 | $2.50 |
| Results tracked | 6 | 3 |
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Category by category
Coding Hy4 preview leads
GPT-5.1-Codex: 41.9 (#116), Hy4 preview: 51.6 (#38)
| Benchmark | GPT-5.1-Codex | Hy4 preview |
|---|---|---|
| LMArena WebDev | 1337 | 1632 |
| SWE-bench Verified (bash only) | 66% | — |
| ALE-Bench | 1,245 | — |
Agentic & Tool Use Not comparable
GPT-5.1-Codex: 38.0 (#33), Hy4 preview: —
| Benchmark | GPT-5.1-Codex | Hy4 preview |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |
Reasoning Not comparable
GPT-5.1-Codex: —, Hy4 preview: 31.9 (#79)
| Benchmark | GPT-5.1-Codex | Hy4 preview |
|---|---|---|
| NYT Connections (extended) | — | 68.2% |
Math Hy4 preview leads
GPT-5.1-Codex: 30.3 (#235), Hy4 preview: 55.7 (#42)
| Benchmark | GPT-5.1-Codex | Hy4 preview |
|---|---|---|
| ProofBench | 9% | 75% |
Frequently asked questions
Is GPT-5.1-Codex better than Hy4 preview?
Hy4 preview is the stronger model overall, scoring 45.3 to 38.6 on the Noometry Index.
Which is cheaper, GPT-5.1-Codex or Hy4 preview?
Hy4 preview is cheaper. It lists at $0.83 per million input tokens and $2.50 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.
Is GPT-5.1-Codex or Hy4 preview better for coding?
Hy4 preview scores higher on coding benchmarks: 51.6 versus 41.9 in the Noometry coding category.
Which has the bigger context window?
Hy4 preview does, with 1.05M tokens against 400K.
How many benchmarks do GPT-5.1-Codex and Hy4 preview share?
2 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Hy4 preview has 3.