Model comparison
GPT-5.3 Codex vs Phi 3 Small 8k Instruct
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 28.8 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 27.4.
- Phi 3 Small 8k Instruct has downloadable open weights; the other is API-only.
Side by side
| GPT-5.3 Codex | Phi 3 Small 8k Instruct | |
|---|---|---|
| Provider | OpenAI | Microsoft |
| Noometry Index | 45.5 | 28.8 |
| 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 | 32 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.5 (#51), Phi 3 Small 8k Instruct: 27.4 (#313)
| Benchmark | GPT-5.3 Codex | Phi 3 Small 8k Instruct |
|---|---|---|
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1408 | — |
| WeirdML | 79.3% | — |
| LiveBench Coding | — | 20.3% |
| LMArena Coding | — | 1102 |
| ALE-Bench | 1,655 | — |
Agentic & Tool Use Not comparable
GPT-5.3 Codex: 47.8 (#9), Phi 3 Small 8k Instruct: —
| Benchmark | GPT-5.3 Codex | Phi 3 Small 8k Instruct |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |
Reasoning Not comparable
GPT-5.3 Codex: —, Phi 3 Small 8k Instruct: 14.2 (#319)
| Benchmark | GPT-5.3 Codex | Phi 3 Small 8k Instruct |
|---|---|---|
| LiveBench Reasoning | — | 15.9% |
| LMArena Hard Prompts | — | 1100 |
| LiveBench Data Analysis | — | 30.3% |
| Adversarial NLI | — | 58.1% |
| BIG-Bench Hard | — | 79.1% |
| Epoch Capabilities Index | 156.84 | — |
| HellaSwag | — | 77% |
| LiveBench | — | 24% |
| WinoGrande | — | 81.5% |
Math Not comparable
GPT-5.3 Codex: —, Phi 3 Small 8k Instruct: 25.4 (#247)
| Benchmark | GPT-5.3 Codex | Phi 3 Small 8k Instruct |
|---|---|---|
| LiveBench Math | — | 17.6% |
| LMArena Math | — | 1151 |
Knowledge Not comparable
GPT-5.3 Codex: —, Phi 3 Small 8k Instruct: 28.5 (#237)
| Benchmark | GPT-5.3 Codex | Phi 3 Small 8k Instruct |
|---|---|---|
| LMArena Expert | — | 1067 |
| ARC (AI2) Challenge | — | 90.7% |
| MMLU | — | 75.7% |
| OpenBookQA | — | 88% |
| TriviaQA | — | 58.1% |
Multilingual Not comparable
GPT-5.3 Codex: —, Phi 3 Small 8k Instruct: 28.6 (#267)
| Benchmark | GPT-5.3 Codex | Phi 3 Small 8k Instruct |
|---|---|---|
| LMArena Non-English | — | 1058 |
| LMArena Chinese | — | 1061 |
| LMArena French | — | 1134 |
| LMArena German | — | 1080 |
| LMArena Japanese | — | 966 |
| LMArena Korean | — | 894 |
| LMArena Russian | — | 1111 |
| LMArena Spanish | — | 1111 |
Instruction Following Not comparable
GPT-5.3 Codex: —, Phi 3 Small 8k Instruct: 52.2 (#287)
| Benchmark | GPT-5.3 Codex | Phi 3 Small 8k Instruct |
|---|---|---|
| LiveBench Instruction Following | — | 47.2% |
| LMArena Instruction Following | — | 1087 |
Long Context Not comparable
GPT-5.3 Codex: —, Phi 3 Small 8k Instruct: 33.0 (#262)
| Benchmark | GPT-5.3 Codex | Phi 3 Small 8k Instruct |
|---|---|---|
| LMArena Longer Query | — | 1088 |
Writing & Preference Not comparable
GPT-5.3 Codex: —, Phi 3 Small 8k Instruct: 31.3 (#279)
| Benchmark | GPT-5.3 Codex | Phi 3 Small 8k Instruct |
|---|---|---|
| LMArena Text | — | 1110 |
| LMArena Creative Writing | — | 1083 |
| LMArena Multi-Turn | — | 1068 |
| LiveBench Language | — | 12.9% |
Frequently asked questions
Is GPT-5.3 Codex better than Phi 3 Small 8k Instruct?
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 28.8 on the Noometry Index.
Is GPT-5.3 Codex or Phi 3 Small 8k Instruct better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.5 versus 27.4 in the Noometry coding category.
How many benchmarks do GPT-5.3 Codex and Phi 3 Small 8k Instruct share?
0 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Phi 3 Small 8k Instruct has 32.