Model comparison
C4ai Aya Expanse 8b vs GPT-5-Codex
GPT-5-Codex is the stronger model overall, scoring 37.3 to 34.3 on the Noometry Index.
Last verified . 0 shared benchmarks.
CohereSummary
- The widest gap is in coding, where GPT-5-Codex leads 41.9 to 33.2.
- GPT-5-Codex accepts more context: 400K tokens versus 8K.
- C4ai Aya Expanse 8b has downloadable open weights; the other is API-only.
Side by side
| C4ai Aya Expanse 8b | GPT-5-Codex | |
|---|---|---|
| Provider | Cohere | OpenAI |
| Noometry Index | 34.3 | 37.3 |
| Released | 2024-10-24 | 2025-09-15 |
| Weights | Open | Proprietary |
| Context window | 8K | 400K |
| Max output | 4K | 128K |
| Input $ / M tokens | — | $1.25 |
| Output $ / M tokens | — | $10 |
| Results tracked | 15 | 3 |
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Category by category
Coding GPT-5-Codex leads
C4ai Aya Expanse 8b: 33.2 (#252), GPT-5-Codex: 41.9 (#100)
| Benchmark | C4ai Aya Expanse 8b | GPT-5-Codex |
|---|---|---|
| WeirdML | — | 54.5% |
| LMArena Coding | 1161 | — |
Agentic & Tool Use Not comparable
C4ai Aya Expanse 8b: —, GPT-5-Codex: 30.8 (#66)
| Benchmark | C4ai Aya Expanse 8b | GPT-5-Codex |
|---|---|---|
| Terminal-Bench | — | 44.3% |
Reasoning GPT-5-Codex leads
C4ai Aya Expanse 8b: 21.4 (#198), GPT-5-Codex: 30.0 (#80)
| Benchmark | C4ai Aya Expanse 8b | GPT-5-Codex |
|---|---|---|
| Kagi LLM Benchmark | — | 70.3% |
| LMArena Hard Prompts | 1156 | — |
Math Not comparable
C4ai Aya Expanse 8b: 30.8 (#204), GPT-5-Codex: —
| Benchmark | C4ai Aya Expanse 8b | GPT-5-Codex |
|---|---|---|
| LMArena Math | 1168 | — |
Knowledge Not comparable
C4ai Aya Expanse 8b: 33.0 (#197), GPT-5-Codex: —
| Benchmark | C4ai Aya Expanse 8b | GPT-5-Codex |
|---|---|---|
| Vectara Hallucination Rate | 9.5% | — |
| LMArena Expert | 1153 | — |
Multilingual Not comparable
C4ai Aya Expanse 8b: 36.3 (#237), GPT-5-Codex: —
| Benchmark | C4ai Aya Expanse 8b | GPT-5-Codex |
|---|---|---|
| LMArena Non-English | 1180 | — |
| LMArena Chinese | 1181 | — |
| LMArena German | 1188 | — |
| LMArena Japanese | 1120 | — |
| LMArena Russian | 1197 | — |
Instruction Following Not comparable
C4ai Aya Expanse 8b: 60.4 (#248), GPT-5-Codex: —
| Benchmark | C4ai Aya Expanse 8b | GPT-5-Codex |
|---|---|---|
| LMArena Instruction Following | 1155 | — |
Long Context Not comparable
C4ai Aya Expanse 8b: 36.1 (#231), GPT-5-Codex: —
| Benchmark | C4ai Aya Expanse 8b | GPT-5-Codex |
|---|---|---|
| LMArena Longer Query | 1192 | — |
Writing & Preference Not comparable
C4ai Aya Expanse 8b: 39.2 (#245), GPT-5-Codex: —
| Benchmark | C4ai Aya Expanse 8b | GPT-5-Codex |
|---|---|---|
| LMArena Text | 1185 | — |
| LMArena Creative Writing | 1168 | — |
| LMArena Multi-Turn | 1160 | — |
Frequently asked questions
Is C4ai Aya Expanse 8b better than GPT-5-Codex?
GPT-5-Codex is the stronger model overall, scoring 37.3 to 34.3 on the Noometry Index.
Is C4ai Aya Expanse 8b or GPT-5-Codex better for coding?
GPT-5-Codex scores higher on coding benchmarks: 41.9 versus 33.2 in the Noometry coding category.
Which has the bigger context window?
GPT-5-Codex does, with 400K tokens against 8K.
How many benchmarks do C4ai Aya Expanse 8b and GPT-5-Codex share?
0 benchmarks have published results for both models. C4ai Aya Expanse 8b has 15 scored results on Noometry and GPT-5-Codex has 3.