Model comparison
GPT-5.3 Codex vs Phi 3 Mini 128k Instruct
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 29.1 on the Noometry Index.
Last verified . 0 shared benchmarks.
MicrosoftSummary
- The widest gap is in coding, where GPT-5.3 Codex leads 48.5 to 28.3.
- Phi 3 Mini 128k Instruct has downloadable open weights; the other is API-only.
Side by side
| GPT-5.3 Codex | Phi 3 Mini 128k Instruct | |
|---|---|---|
| Provider | OpenAI | Microsoft |
| Noometry Index | 45.5 | 29.1 |
| Released | 2026-02-05 | 2024-04-23 |
| Weights | Proprietary | Open |
| Context window | 400K | — |
| Max output | 128K | — |
| Input $ / M tokens | $1.75 | — |
| Output $ / M tokens | $14 | — |
| Results tracked | 8 | 19 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.5 (#51), Phi 3 Mini 128k Instruct: 28.3 (#307)
| Benchmark | GPT-5.3 Codex | Phi 3 Mini 128k Instruct |
|---|---|---|
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1408 | — |
| WeirdML | 79.3% | — |
| BigCodeBench Instruct | — | 29.6% |
| LMArena Coding | — | 1040 |
| BigCodeBench Complete | — | 40.6% |
| ALE-Bench | 1,655 | — |
Agentic & Tool Use Not comparable
GPT-5.3 Codex: 47.8 (#9), Phi 3 Mini 128k Instruct: —
| Benchmark | GPT-5.3 Codex | Phi 3 Mini 128k Instruct |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |
Reasoning Not comparable
GPT-5.3 Codex: —, Phi 3 Mini 128k Instruct: 18.7 (#254)
| Benchmark | GPT-5.3 Codex | Phi 3 Mini 128k Instruct |
|---|---|---|
| LMArena Hard Prompts | — | 1028 |
| Epoch Capabilities Index | 156.84 | — |
Math Not comparable
GPT-5.3 Codex: —, Phi 3 Mini 128k Instruct: 29.2 (#220)
| Benchmark | GPT-5.3 Codex | Phi 3 Mini 128k Instruct |
|---|---|---|
| LMArena Math | — | 1089 |
Knowledge Not comparable
GPT-5.3 Codex: —, Phi 3 Mini 128k Instruct: 26.3 (#251)
| Benchmark | GPT-5.3 Codex | Phi 3 Mini 128k Instruct |
|---|---|---|
| LMArena Expert | — | 984 |
Multilingual Not comparable
GPT-5.3 Codex: —, Phi 3 Mini 128k Instruct: 25.4 (#280)
| Benchmark | GPT-5.3 Codex | Phi 3 Mini 128k Instruct |
|---|---|---|
| LMArena Non-English | — | 1000 |
| LMArena Chinese | — | 1016 |
| LMArena French | — | 1038 |
| LMArena German | — | 1006 |
| LMArena Japanese | — | 899 |
| LMArena Korean | — | 856 |
| LMArena Russian | — | 1004 |
| LMArena Spanish | — | 1058 |
Instruction Following Not comparable
GPT-5.3 Codex: —, Phi 3 Mini 128k Instruct: 52.1 (#289)
| Benchmark | GPT-5.3 Codex | Phi 3 Mini 128k Instruct |
|---|---|---|
| LMArena Instruction Following | — | 1023 |
Long Context Not comparable
GPT-5.3 Codex: —, Phi 3 Mini 128k Instruct: 30.3 (#284)
| Benchmark | GPT-5.3 Codex | Phi 3 Mini 128k Instruct |
|---|---|---|
| LMArena Longer Query | — | 996 |
Writing & Preference Not comparable
GPT-5.3 Codex: —, Phi 3 Mini 128k Instruct: 27.3 (#296)
| Benchmark | GPT-5.3 Codex | Phi 3 Mini 128k Instruct |
|---|---|---|
| LMArena Text | — | 1050 |
| LMArena Creative Writing | — | 1024 |
| LMArena Multi-Turn | — | 989 |
Frequently asked questions
Is GPT-5.3 Codex better than Phi 3 Mini 128k Instruct?
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 29.1 on the Noometry Index.
Is GPT-5.3 Codex or Phi 3 Mini 128k Instruct better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.5 versus 28.3 in the Noometry coding category.
How many benchmarks do GPT-5.3 Codex and Phi 3 Mini 128k Instruct share?
0 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Phi 3 Mini 128k Instruct has 19.