Data points: 97
Model compare
The readout for GPT-4o 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 6.7 to 93.3.
Evidence depth
97 data points
Includes 17 benchmark rows, 0 audit samples, and 6 provider examples.
Selection signal
Start with GPT-5.1 Codex
The charts below split 23 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-4o and GPT-5.1 Codex: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Model compare | GPT-4o | GPT-5.1 Codex |
|---|---|---|
| Overall leader | Contender | Leading |
| Weighted overall score | 6.7 pts | 93.3 pts |
| Benchmark category leads | 0 categories | 6 categories |
| Operational advantages | Free providers | Cheapest input price, Provider coverage |
| Context window | 128K tokens | 400K tokens |
| Max output | 16.4K tokens | 128K tokens |
| Modalities | Input TextImageFile Output Text |
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-4o | GPT-5.1 Codex |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Released | Nov 2024 | Nov 2025 |
| Parameters | No data | No data |
| Tokenizer | GPT | GPT |
| Knowledge cutoff | 2023-10-31 | No data |
| OpenRouter ID | openai/gpt-4o | openai/gpt-5.1-codex |
| References | No data | No data |
This report only uses LMSpeed data for GPT-4o and GPT-5.1 Codex: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
GPT-4o
GPT-4o has these operational advantages: Free providers.
GPT-5.1 Codex
GPT-5.1 Codex is stronger in benchmark categories (Agents, Coding, Reasoning, Knowledge, Math) and operational dimensions (Cheapest input price, Provider coverage).
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-4o
43.2
Avg. score
GPT-5.1 Codex
52.4
GPT-5.1 Codex leads by 11.0
GPT-5.1 Codex leads by 4.4
GPT-5.1 Codex leads by 15.7
GPT-5.1 Codex leads by 1.2
GPT-5.1 Codex leads by 11.6
No data
No data
GPT-5.1 Codex leads by 11.4
Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.
GPT-4o
$2.50/M
Rank #131/162 · confidence 4
GPT-5.1 Codex
winner$1.25/M
Rank #107/162 · confidence 4
GPT-4o
$4.38/M
Rank #127/162 · confidence 4
GPT-5.1 Codex
winner$3.44/M
Rank #117/162 · confidence 4
GPT-4o
$10.00/M
Rank #120/162 · confidence 4
GPT-5.1 Codex
$10.00/M
Rank #120/162 · confidence 4
GPT-4o
74.8%
Rank #90/125 · confidence 4
GPT-5.1 Codex
winner86.0%
Rank #20/125 · confidence 4
GPT-4o
54.3%
Rank #156/188 · confidence 4
GPT-5.1 Codex
winner86.0%
Rank #41/188 · confidence 4
GPT-4o
3.3%
Rank #180/187 · confidence 4
GPT-5.1 Codex
winner23.4%
Rank #47/187 · confidence 4
GPT-4o
30.9%
Rank #88/115 · confidence 4
GPT-5.1 Codex
winner84.9%
Rank #9/115 · confidence 4
GPT-4o
33.3
Rank #80/96 · confidence 1 · eval date 2024-05-13
GPT-5.1 Codex
winner40.2
Rank #56/96 · confidence 1 · eval date 2025-10-15
GPT-4o
33.3%
Rank #120/185 · confidence 4
GPT-5.1 Codex
winner40.2%
Rank #68/185 · confidence 4
GPT-4o
19.7
Rank #75/90 · confidence 1 · eval date 2024-05-13
GPT-5.1 Codex
winner39.2
Rank #23/90 · confidence 1 · eval date 2025-10-15
GPT-4o
54.3
Rank #91/96 · confidence 1 · eval date 2024-05-13
GPT-5.1 Codex
winner86.0
Rank #40/96 · confidence 1 · eval date 2025-10-15
GPT-4o
3.3
Rank #94/96 · confidence 1 · eval date 2024-05-13
GPT-5.1 Codex
winner23.4
Rank #45/96 · confidence 1 · eval date 2025-10-15
GPT-4o
11.2
Rank #90/99 · confidence 1 · eval date 2024-05-13
GPT-5.1 Codex
winner34.7
Rank #46/99 · confidence 1 · eval date 2025-10-15
GPT-4o
37.9
Rank #75/90 · confidence 1 · eval date 2024-05-13
GPT-5.1 Codex
winner74.4
Rank #47/90 · confidence 1 · eval date 2025-10-15
GPT-4o
861.0
Rank #65/66 · confidence 1 · eval date 2024-05-13
GPT-5.1 Codex
winner1191.0
Rank #47/66 · confidence 1 · eval date 2025-10-15
GPT-4o
34.3
Rank #82/86 · confidence 1 · eval date 2024-05-13
GPT-5.1 Codex
winner70.0
Rank #39/86 · confidence 1 · eval date 2025-10-15
GPT-4o
25.1
Rank #75/84 · confidence 1 · eval date 2024-05-13
GPT-5.1 Codex
winner83.0
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-4o | 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-4o | GPT-5.1 Codex |
|---|---|---|
20 tests | GPT-4o speed / latency 88 tok/s / 1593ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
10 tests | GPT-4o speed / latency 57 tok/s / 3381ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
5 tests | GPT-4o speed / latency 48 tok/s / 13138ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
5 tests | GPT-4o speed / latency 58 tok/s / 2583ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
3 tests | GPT-4o speed / latency 40 tok/s / 2993ms input / output No data | GPT-5.1 Codex speed / latency N/A / N/A input / output No data |
GPT-4o gpt-4o 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%.
Input
Output
| Features | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeWeb search | Text inputImage inputText outputTool callingStructured outputsJSON modeReasoning |
|---|
