# GPT-5.3 Codex vs phi-3-medium 14B

> GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 29.1 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-3-codex-vs-phi-3-medium-14b
- Last updated: 2026-10-10
- Shared benchmarks: 1

## Summary

- They share 1 benchmark with published results for both. GPT-5.3 Codex scores higher in 1 category and phi-3-medium 14B in 0 categories; one gap is clear of the uncertainty.
- The widest gap is in coding, where GPT-5.3 Codex leads 48.5 to 36.3.
- phi-3-medium 14B has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.3 Codex | phi-3-medium 14B |
|---|---|---|
| Provider | OpenAI | Microsoft |
| Noometry Index | 45.5 | 29.1 |
| Rank | 61 | 306 |
| Context | 400K | — |
| Input $/M | $1.75 | — |
| Output $/M | $14 | — |
| Weights | Proprietary | Open |

## Coding

- GPT-5.3 Codex: 48.5 (#51)
- phi-3-medium 14B: 36.3 (#198)

| Benchmark | GPT-5.3 Codex | phi-3-medium 14B |
|---|---|---|
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1408 | — |
| WeirdML | 79.3% | — |
| BigCodeBench Instruct | — | 37.6% |
| BigCodeBench Complete | — | 48.7% |
| ALE-Bench | 1,655 | — |

## Agentic & Tool Use

- GPT-5.3 Codex: 47.8 (#9)
- phi-3-medium 14B: —

| Benchmark | GPT-5.3 Codex | phi-3-medium 14B |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |

## Reasoning

- GPT-5.3 Codex: —
- phi-3-medium 14B: —

| Benchmark | GPT-5.3 Codex | phi-3-medium 14B |
|---|---|---|
| Epoch Capabilities Index | 156.84 | 121.18 |
| Adversarial NLI | — | 55.8% |
| BIG-Bench Hard | — | 81.4% |
| HellaSwag | — | 82.4% |
| WinoGrande | — | 81.5% |

## Math

- GPT-5.3 Codex: —
- phi-3-medium 14B: 25.2 (#249)

| Benchmark | GPT-5.3 Codex | phi-3-medium 14B |
|---|---|---|
| MATH Level 5 | — | 17.6% |

## Knowledge

- GPT-5.3 Codex: —
- phi-3-medium 14B: 9.1 (#301)

| Benchmark | GPT-5.3 Codex | phi-3-medium 14B |
|---|---|---|
| GPQA Diamond | — | 27.6% |
| ARC (AI2) Challenge | — | 91.6% |
| MMLU | — | 78% |
| OpenBookQA | — | 87.4% |
| TriviaQA | — | 73.9% |

## FAQ

### Is GPT-5.3 Codex better than phi-3-medium 14B?

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-medium 14B better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.5 versus 36.3 in the Noometry coding category.

### How many benchmarks do GPT-5.3 Codex and phi-3-medium 14B share?

1 benchmark has published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and phi-3-medium 14B has 13.