Model comparison
GPT-5.3 Codex vs Phi 3 Medium 4k Instruct
GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 33.0 on the Noometry Index.
Last verified . 0 shared benchmarks.
MicrosoftSummary
- The widest gap is in coding, where GPT-5.3 Codex leads 48.6 to 32.9.
- Phi 3 Medium 4k Instruct has downloadable open weights; the other is API-only.
Side by side
| GPT-5.3 Codex | Phi 3 Medium 4k Instruct | |
|---|---|---|
| Provider | OpenAI | Microsoft |
| Noometry Index | 45.8 | 33.0 |
| Released | 2026-02-05 | — |
| Weights | Proprietary | Open |
| Context window | 400K | — |
| Max output | 128K | — |
| Input $ / M tokens | $1.75 | — |
| Output $ / M tokens | $14 | — |
| Results tracked | 8 | 17 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.6 (#56), Phi 3 Medium 4k Instruct: 32.9 (#268)
| Benchmark | GPT-5.3 Codex | Phi 3 Medium 4k Instruct |
|---|---|---|
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1409 | — |
| WeirdML | 79.3% | — |
| LMArena Coding | — | 1130 |
| ALE-Bench | 1,655 | — |
Agentic & Tool Use Not comparable
GPT-5.3 Codex: 48.0 (#9), Phi 3 Medium 4k Instruct: —
| Benchmark | GPT-5.3 Codex | Phi 3 Medium 4k Instruct |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |
Reasoning Not comparable
GPT-5.3 Codex: —, Phi 3 Medium 4k Instruct: 21.7 (#214)
| Benchmark | GPT-5.3 Codex | Phi 3 Medium 4k Instruct |
|---|---|---|
| LMArena Hard Prompts | — | 1127 |
| Epoch Capabilities Index | 156.77 | — |
Math Not comparable
GPT-5.3 Codex: —, Phi 3 Medium 4k Instruct: 33.4 (#202)
| Benchmark | GPT-5.3 Codex | Phi 3 Medium 4k Instruct |
|---|---|---|
| LMArena Math | — | 1173 |
Knowledge Not comparable
GPT-5.3 Codex: —, Phi 3 Medium 4k Instruct: 30.2 (#229)
| Benchmark | GPT-5.3 Codex | Phi 3 Medium 4k Instruct |
|---|---|---|
| LMArena Expert | — | 1108 |
Multilingual Not comparable
GPT-5.3 Codex: —, Phi 3 Medium 4k Instruct: 30.6 (#263)
| Benchmark | GPT-5.3 Codex | Phi 3 Medium 4k Instruct |
|---|---|---|
| LMArena Non-English | — | 1094 |
| LMArena Chinese | — | 1108 |
| LMArena French | — | 1110 |
| LMArena German | — | 1101 |
| LMArena Japanese | — | 1042 |
| LMArena Korean | — | 954 |
| LMArena Russian | — | 1145 |
| LMArena Spanish | — | 1095 |
Instruction Following Not comparable
GPT-5.3 Codex: —, Phi 3 Medium 4k Instruct: 57.6 (#268)
| Benchmark | GPT-5.3 Codex | Phi 3 Medium 4k Instruct |
|---|---|---|
| LMArena Instruction Following | — | 1113 |
Long Context Not comparable
GPT-5.3 Codex: —, Phi 3 Medium 4k Instruct: 34.0 (#255)
| Benchmark | GPT-5.3 Codex | Phi 3 Medium 4k Instruct |
|---|---|---|
| LMArena Longer Query | — | 1120 |
Writing & Preference Not comparable
GPT-5.3 Codex: —, Phi 3 Medium 4k Instruct: 34.1 (#272)
| Benchmark | GPT-5.3 Codex | Phi 3 Medium 4k Instruct |
|---|---|---|
| LMArena Text | — | 1138 |
| LMArena Creative Writing | — | 1107 |
| LMArena Multi-Turn | — | 1088 |
Frequently asked questions
Is GPT-5.3 Codex better than Phi 3 Medium 4k Instruct?
GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 33.0 on the Noometry Index.
Is GPT-5.3 Codex or Phi 3 Medium 4k Instruct better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 32.9 in the Noometry coding category.
How many benchmarks do GPT-5.3 Codex and Phi 3 Medium 4k Instruct share?
0 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Phi 3 Medium 4k Instruct has 17.