Model comparison
GPT-5.1-Codex vs MiMo-V2.5
MiMo-V2.5 is the stronger model overall, scoring 43.4 to 38.6 on the Noometry Index.
Last verified . 3 shared benchmarks.
Summary
- They share 3 benchmarks with published results for both. GPT-5.1-Codex scores higher in 0 categories and MiMo-V2.5 in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in math, where MiMo-V2.5 leads 36.8 to 30.3.
- The biggest single-benchmark swing is ProofBench: 9% for GPT-5.1-Codex and 16% for MiMo-V2.5.
- MiMo-V2.5 is cheaper at $0.14 / $0.28 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
- MiMo-V2.5 accepts more context: 1.05M tokens versus 400K.
- MiMo-V2.5 has downloadable open weights; the other is API-only.
Side by side
| GPT-5.1-Codex | MiMo-V2.5 | |
|---|---|---|
| Provider | OpenAI | Xiaomi |
| Noometry Index | 38.6 | 43.4 |
| Released | 2025-11-12 | 2026-04-22 |
| Weights | Proprietary | Open |
| Context window | 400K | 1.05M |
| Max output | 128K | 131K |
| Input $ / M tokens | $1.25 | $0.14 |
| Output $ / M tokens | $10 | $0.28 |
| Results tracked | 6 | 23 |
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Category by category
Coding MiMo-V2.5 leads
GPT-5.1-Codex: 41.9 (#116), MiMo-V2.5: 43.9 (#81)
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| LMArena WebDev | 1337 | 1438 |
| ALE-Bench | 1,245 | 513.95 |
| SWE-bench Verified (bash only) | 66% | — |
| SciCode | — | 43.1% |
| LMArena Coding | — | 1469 |
Agentic & Tool Use Not comparable
GPT-5.1-Codex: 38.0 (#33), MiMo-V2.5: —
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |
Reasoning Not comparable
GPT-5.1-Codex: —, MiMo-V2.5: 28.6 (#101)
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| CritPt | — | 3.7% |
| LMArena Hard Prompts | — | 1450 |
Math MiMo-V2.5 leads
GPT-5.1-Codex: 30.3 (#235), MiMo-V2.5: 36.8 (#163)
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| ProofBench | 9% | 16% |
| LMArena Math | — | 1436 |
Knowledge Not comparable
GPT-5.1-Codex: —, MiMo-V2.5: 40.8 (#115)
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| LMArena Expert | — | 1460 |
Multimodal Not comparable
GPT-5.1-Codex: —, MiMo-V2.5: 39.8 (#54)
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| LMArena Vision | — | 1247 |
Multilingual Not comparable
GPT-5.1-Codex: —, MiMo-V2.5: 51.9 (#99)
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| LMArena Non-English | — | 1404 |
| LMArena Chinese | — | 1468 |
| LMArena French | — | 1447 |
| LMArena German | — | 1421 |
| LMArena Japanese | — | 1306 |
| LMArena Korean | — | 1363 |
| LMArena Russian | — | 1395 |
| LMArena Spanish | — | 1416 |
Instruction Following Not comparable
GPT-5.1-Codex: —, MiMo-V2.5: 75.5 (#60)
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| LMArena Instruction Following | — | 1434 |
Long Context Not comparable
GPT-5.1-Codex: —, MiMo-V2.5: 44.2 (#73)
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| LMArena Longer Query | — | 1445 |
Writing & Preference Not comparable
GPT-5.1-Codex: —, MiMo-V2.5: 61.6 (#86)
| Benchmark | GPT-5.1-Codex | MiMo-V2.5 |
|---|---|---|
| LMArena Text | — | 1428 |
| LMArena Creative Writing | — | 1393 |
| LMArena Multi-Turn | — | 1445 |
Frequently asked questions
Is GPT-5.1-Codex better than MiMo-V2.5?
MiMo-V2.5 is the stronger model overall, scoring 43.4 to 38.6 on the Noometry Index.
Which is cheaper, GPT-5.1-Codex or MiMo-V2.5?
MiMo-V2.5 is cheaper. It lists at $0.14 per million input tokens and $0.28 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.
Is GPT-5.1-Codex or MiMo-V2.5 better for coding?
MiMo-V2.5 scores higher on coding benchmarks: 43.9 versus 41.9 in the Noometry coding category.
Which has the bigger context window?
MiMo-V2.5 does, with 1.05M tokens against 400K.
How many benchmarks do GPT-5.1-Codex and MiMo-V2.5 share?
3 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and MiMo-V2.5 has 23.