Model comparison
GPT-5.3 Codex vs Grok-2 (Dec 2024)
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 33.4 on the Noometry Index.
Last verified . 2 shared benchmarks.
Summary
- They share 2 benchmarks with published results for both. GPT-5.3 Codex scores higher in 1 category and Grok-2 (Dec 2024) 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 32.9.
- The biggest single-benchmark swing is WeirdML: 79.3% for GPT-5.3 Codex and 22.2% for Grok-2 (Dec 2024).
Side by side
| GPT-5.3 Codex | Grok-2 (Dec 2024) | |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 45.5 | 33.4 |
| Released | 2026-02-05 | 2024-08-13 |
| Weights | Proprietary | Proprietary |
| Context window | 400K | — |
| Max output | 128K | — |
| Input $ / M tokens | $1.75 | — |
| Output $ / M tokens | $14 | — |
| Results tracked | 8 | 34 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.5 (#51), Grok-2 (Dec 2024): 32.9 (#254)
| Benchmark | GPT-5.3 Codex | Grok-2 (Dec 2024) |
|---|---|---|
| WeirdML | 79.3% | 22.2% |
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1408 | — |
| LiveBench Coding | — | 46.4% |
| LMArena Coding | — | 1288 |
| ALE-Bench | 1,655 | — |
Agentic & Tool Use Not comparable
GPT-5.3 Codex: 47.8 (#9), Grok-2 (Dec 2024): —
| Benchmark | GPT-5.3 Codex | Grok-2 (Dec 2024) |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |
Reasoning Not comparable
GPT-5.3 Codex: —, Grok-2 (Dec 2024): 16.4 (#294)
| Benchmark | GPT-5.3 Codex | Grok-2 (Dec 2024) |
|---|---|---|
| Epoch Capabilities Index | 156.84 | 130.48 |
| SimpleBench | — | 22.7% |
| LiveBench Reasoning | — | 54.8% |
| LMArena Hard Prompts | — | 1272 |
| DTBench | — | 65.2% |
| LiveBench Data Analysis | — | 54.5% |
| LiveBench | — | 54.3% |
Math Not comparable
GPT-5.3 Codex: —, Grok-2 (Dec 2024): 19.6 (#278)
| Benchmark | GPT-5.3 Codex | Grok-2 (Dec 2024) |
|---|---|---|
| OTIS Mock AIME 2024-2025 | — | 11.5% |
| LiveBench Math | — | 54.9% |
| LMArena Math | — | 1283 |
| MATH Level 5 | — | 63.5% |
| FrontierMath (Feb 2025 set) | — | 0.7% |
Knowledge Not comparable
GPT-5.3 Codex: —, Grok-2 (Dec 2024): 29.8 (#225)
| Benchmark | GPT-5.3 Codex | Grok-2 (Dec 2024) |
|---|---|---|
| GPQA Diamond | — | 53.8% |
| Confabulations | — | 20.1% |
| LMArena Expert | — | 1254 |
Multilingual Not comparable
GPT-5.3 Codex: —, Grok-2 (Dec 2024): 43.3 (#183)
| Benchmark | GPT-5.3 Codex | Grok-2 (Dec 2024) |
|---|---|---|
| LMArena Non-English | — | 1282 |
| LMArena Chinese | — | 1289 |
| LMArena French | — | 1317 |
| LMArena German | — | 1287 |
| LMArena Japanese | — | 1244 |
| LMArena Korean | — | 1237 |
| LMArena Russian | — | 1286 |
| LMArena Spanish | — | 1281 |
Instruction Following Not comparable
GPT-5.3 Codex: —, Grok-2 (Dec 2024): 67.1 (#197)
| Benchmark | GPT-5.3 Codex | Grok-2 (Dec 2024) |
|---|---|---|
| LiveBench Instruction Following | — | 69.6% |
| LMArena Instruction Following | — | 1270 |
Long Context Not comparable
GPT-5.3 Codex: —, Grok-2 (Dec 2024): 38.7 (#186)
| Benchmark | GPT-5.3 Codex | Grok-2 (Dec 2024) |
|---|---|---|
| LMArena Longer Query | — | 1276 |
Writing & Preference Not comparable
GPT-5.3 Codex: —, Grok-2 (Dec 2024): 48.8 (#192)
| Benchmark | GPT-5.3 Codex | Grok-2 (Dec 2024) |
|---|---|---|
| LMArena Text | — | 1305 |
| LMArena Creative Writing | — | 1284 |
| Short-Story Creative Writing | — | 63.6% |
| LMArena Multi-Turn | — | 1290 |
| LiveBench Language | — | 45.6% |
Frequently asked questions
Is GPT-5.3 Codex better than Grok-2 (Dec 2024)?
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 33.4 on the Noometry Index.
Is GPT-5.3 Codex or Grok-2 (Dec 2024) better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.5 versus 32.9 in the Noometry coding category.
How many benchmarks do GPT-5.3 Codex and Grok-2 (Dec 2024) share?
2 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Grok-2 (Dec 2024) has 34.