Data points: 107
Model compare
The readout for GPT-5 and GPT-5.1 Codex, before the detailed comparison sheet.
Weighted outcome: GPT-5.1 Codex. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Decision read
GPT-5.1 Codex
GPT-5.1 Codex has the higher weighted result; Model A / B score 46.7 to 53.3.
Evidence depth
107 data points
Includes 22 benchmark rows, 0 audit samples, and 6 provider examples.
Selection signal
Start with GPT-5.1 Codex
The charts below split 28 high-signal samples across speed, scores, and audit health.
Switch either side of this report to compare another model with the same LMSpeed data pipeline.
Select a different model to open a new comparison URL.
This report only uses LMSpeed data for GPT-5 and GPT-5.1 Codex: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Model compare | GPT-5 | GPT-5.1 Codex |
|---|---|---|
| Overall leader | Contender | Leading |
| Weighted overall score | 46.7 pts | 53.3 pts |
| Benchmark category leads | 2 categories | 4 categories |
| Operational advantages | Cheapest input price, Free providers, Provider coverage | No data |
| Context window | 400K tokens | 400K tokens |
| Max output | 128K tokens | 128K tokens |
| Modalities | Input TextImageFile Output Text | Input |
The overall result weights benchmark capability categories at 80% and price, API speed/latency, and availability at 20%. Recent test volume does not affect the winner, and missing benchmark categories are excluded.
| Model compare | GPT-5 | GPT-5.1 Codex |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Released | Aug 2025 | Nov 2025 |
| Parameters | No data | No data |
| Tokenizer | GPT | GPT |
| Knowledge cutoff | 2024-09-30 | No data |
| OpenRouter ID | openai/gpt-5 | openai/gpt-5.1-codex |
| References | No data | No data |
This report only uses LMSpeed data for GPT-5 and GPT-5.1 Codex: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
GPT-5
GPT-5 is stronger in benchmark categories (Math, Instruction following) and operational dimensions (Cheapest input price, Free providers, Provider coverage).
GPT-5.1 Codex
GPT-5.1 Codex leads these benchmark categories: Agents, Coding, Reasoning, Knowledge.
Third-party benchmark profile synced into LMSpeed; only metrics available for both models are shown.
Compare benchmark category scores on a 0-100 scale. Select a category to inspect the gap.
Avg. score
GPT-5
51.9
Avg. score
GPT-5.1 Codex
52.4
GPT-5.1 Codex leads by 4.4
GPT-5.1 Codex leads by 1.6
GPT-5.1 Codex leads by 4.3
GPT-5.1 Codex leads by 1.0
GPT-5 leads by 7.8
No data
No data
GPT-5 leads by 0.2
Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.
GPT-5
$1.25/M
Rank #107/162 · confidence 4
GPT-5.1 Codex
$1.25/M
Rank #107/162 · confidence 4
GPT-5
$3.44/M
Rank #117/162 · confidence 4
GPT-5.1 Codex
$3.44/M
Rank #117/162 · confidence 4
GPT-5
$10.00/M
Rank #120/162 · confidence 4
GPT-5.1 Codex
$10.00/M
Rank #120/162 · confidence 4
GPT-5
winner75.6
Rank #2/89 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
67.3
Rank #31/89 · confidence 1 · eval date 2025-10-15
GPT-5
80.6%
Rank #57/125 · confidence 4
GPT-5.1 Codex
winner86.0%
Rank #20/125 · confidence 4
GPT-5
5.7
Rank #30/73 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
5.7
Rank #30/73 · confidence 1 · eval date 2025-10-15
GPT-5
67.3%
Rank #121/188 · confidence 4
GPT-5.1 Codex
winner86.0%
Rank #41/188 · confidence 4
GPT-5
5.4%
Rank #132/187 · confidence 4
GPT-5.1 Codex
winner23.4%
Rank #47/187 · confidence 4
GPT-5
55.8%
Rank #49/115 · confidence 4
GPT-5.1 Codex
winner84.9%
Rank #9/115 · confidence 4
GPT-5
winner20.1
Rank #22/33 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
13.1
Rank #28/33 · confidence 1 · eval date 2025-10-15
GPT-5
winner42.9
Rank #46/96 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
40.2
Rank #56/96 · confidence 1 · eval date 2025-10-15
GPT-5
38.8%
Rank #83/185 · confidence 4
GPT-5.1 Codex
winner40.2%
Rank #68/185 · confidence 4
GPT-5
winner40.7
Rank #20/90 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
39.2
Rank #23/90 · confidence 1 · eval date 2025-10-15
GPT-5
winner82.1
Rank #31/90 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
74.4
Rank #47/90 · confidence 1 · eval date 2025-10-15
GPT-5
winner26.5
Rank #39/96 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
23.4
Rank #45/96 · confidence 1 · eval date 2025-10-15
GPT-5
85.4
Rank #45/96 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
winner86.0
Rank #40/96 · confidence 1 · eval date 2025-10-15
GPT-5
34.7
Rank #48/99 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
winner34.7
Rank #46/99 · confidence 1 · eval date 2025-10-15
GPT-5
winner74.2
Rank #32/57 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
72.5
Rank #36/57 · confidence 1 · eval date 2025-10-15
GPT-5
winner1214.0
Rank #40/66 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
1191.0
Rank #47/66 · confidence 1 · eval date 2025-10-15
GPT-5
winner73.1
Rank #29/86 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
70.0
Rank #39/86 · confidence 1 · eval date 2025-10-15
GPT-5
8.5
Rank #20/20 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
winner26.2
Rank #11/20 · confidence 1 · eval date 2025-10-15
GPT-5
winner84.8
Rank #44/84 · confidence 1 · eval date 2025-08-07
GPT-5.1 Codex
83.0
Rank #50/84 · confidence 1 · eval date 2025-10-15
Latest completed audits from shared providers, with four safety and integrity score groups plus report links.
| Provider | GPT-5 | GPT-5.1 Codex |
|---|---|---|
| No completed audits are available from shared providers yet. | ||
Speed aggregates and input/output pricing share each provider row for real API selection and migration cost checks.
| Provider | GPT-5 | GPT-5.1 Codex |
|---|---|---|
20 tests | GPT-5 speed / latency 95 tok/s / 1234ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
5 tests | GPT-5 speed / latency 45 tok/s / 3704ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
5 tests | GPT-5 speed / latency 46 tok/s / 6577ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
5 tests | GPT-5 speed / latency 102 tok/s / 948ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
5 tests | GPT-5 speed / latency 131 tok/s / 743ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
GPT-5 gpt-5 speed / latency No data input / output $0/request | GPT-5.1 Codex gpt-5.1-codex speed / latency No data input / output $0/request |
Weighted outcome: GPT-5.1 Codex. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Output
| Features | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning | Text inputImage inputText outputTool callingStructured outputsJSON modeReasoning |
|---|
