Key Takeaways
GPT-5.3 Codex wins:
- Larger context window
- Faster response time
- Higher intelligence benchmark
- Better at coding
- Supports vision
- Has reasoning mode
Kimi K2 0905 (exacto) wins:
- Cheaper input tokens
- Cheaper output tokens
- Better at math
Price Advantage
Kimi K2 0905 (exacto)
Benchmark Advantage
GPT-5.3 Codex
Context Window
GPT-5.3 Codex
Speed
GPT-5.3 Codex
Pricing Comparison
Price Comparison
| Metric | GPT-5.3 Codex | Kimi K2 0905 (exacto) | Winner |
|---|---|---|---|
| Input (per 1M tokens) | $1.75 | $0.40 | Kimi K2 0905 (exacto) |
| Output (per 1M tokens) | $14.00 | $2.00 | Kimi K2 0905 (exacto) |
| Cache Read (per 1M) | $0.17 | $0.15 | Kimi K2 0905 (exacto) |
Using a 3:1 input/output ratio, Kimi K2 0905 (exacto) is 83% cheaper overall.
GPT-5.3 Codex Providers
No provider data available
Kimi K2 0905 (exacto) Providers
No provider data available
Benchmark Comparison
6
Benchmarks Compared
3
GPT-5.3 Codex Wins
0
Kimi K2 0905 (exacto) Wins
Benchmark Scores
| Benchmark | GPT-5.3 Codex | Kimi K2 0905 (exacto) | Winner |
|---|---|---|---|
Intelligence Index Overall intelligence score | 54.0 | 30.9 | |
Coding Index Code generation & understanding | 53.1 | 25.9 | |
Math Index Mathematical reasoning | - | 57.3 | - |
MMLU Pro Academic knowledge | - | 81.9 | - |
GPQA Graduate-level science | 91.5 | 76.7 | |
LiveCodeBench Competitive programming | - | 61.0 | - |
GPT-5.3 Codex significantly outperforms in coding benchmarks.
Cost vs Quality
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Other models
Context & Performance
Context Window
GPT-5.3 Codex
400,000
tokens
Kimi K2 0905 (exacto)
262,144
tokens
GPT-5.3 Codex has a 34% larger context window.
Speed Performance
| Metric | GPT-5.3 Codex | Kimi K2 0905 (exacto) | Winner |
|---|---|---|---|
| Tokens/second | 63.8 tok/s | 32.9 tok/s | |
| Time to First Token | 83.49s | 1.09s |
GPT-5.3 Codex responds 94% faster on average.
Capabilities
Feature Comparison
| Feature | GPT-5.3 Codex | Kimi K2 0905 (exacto) |
|---|---|---|
| Vision (Image Input) | ||
| Tool/Function Calls | ||
| Reasoning Mode | ||
| Audio Input | ||
| Audio Output | ||
| PDF Input | ||
| Prompt Caching | ||
| Web Search |
License & Release
| Property | GPT-5.3 Codex | Kimi K2 0905 (exacto) |
|---|---|---|
| License | Proprietary | Open Source |
| Author | OpenAI | Moonshotai |
| Released | Feb 2026 | Sep 2025 |
GPT-5.3 Codex Modalities
Input
textimage
Output
text
Kimi K2 0905 (exacto) Modalities
Input
text
Output
text