Data points: 69
Model compare
The readout for GPT-5.4 and Mercury 2, before the detailed comparison sheet.
Weighted outcome: GPT-5.4. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Decision read
GPT-5.4
GPT-5.4 has the higher weighted result; Model A / B score 90 to 10.
Evidence depth
69 data points
Includes 9 benchmark rows, 0 audit samples, and 5 provider examples.
Selection signal
Start with GPT-5.4
The charts below split 14 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-5.4 and Mercury 2: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Model compare | GPT-5.4 | Mercury 2 |
|---|---|---|
| Overall leader | Leading | Contender |
| Weighted overall score | 90.0 pts | 10.0 pts |
| Benchmark category leads | 2 categories | 0 categories |
| Operational advantages | Free providers, Provider coverage | Average speed, First-token latency |
| Context window | 1.1M tokens | 128K tokens |
| Max output | 128K tokens | 50K 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-5.4 | Mercury 2 |
|---|---|---|
| Developer | OpenAI | Inception |
| Released | Mar 2026 | Mar 2026 |
| Parameters | No data | No data |
| Tokenizer | GPT | Other |
| Knowledge cutoff | No data | No data |
| OpenRouter ID | openai/gpt-5.4 | inception/mercury-2 |
| References | No data | No data |
This report only uses LMSpeed data for GPT-5.4 and Mercury 2: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
GPT-5.4
GPT-5.4 is stronger in benchmark categories (Coding, Reasoning) and operational dimensions (Free providers, Provider coverage).
Mercury 2
Mercury 2 has these operational advantages: Average speed, First-token latency.
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-5.4
57.8
Avg. score
Mercury 2
52.2
GPT-5.4
GPT-5.4 leads by 10.7
GPT-5.4 leads by 7.4
GPT-5.4
GPT-5.4
No data
GPT-5.4
GPT-5.4
Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.
GPT-5.4
96.3 tok/s
Rank #60/139 · confidence 4
Mercury 2
winner1112.3 tok/s
Rank #1/139 · confidence 4
GPT-5.4
winner0.67 s
Rank #22/139 · confidence 4
Mercury 2
3.58 s
Rank #58/139 · confidence 4
GPT-5.4
winner0.67 s
Rank #30/139 · confidence 4
Mercury 2
3.58 s
Rank #105/139 · confidence 4
GPT-5.4
$15.00/M
Rank #138/163 · confidence 4
Mercury 2
winner$0.750/M
Rank #29/163 · confidence 4
GPT-5.4
$5.63/M
Rank #137/163 · confidence 4
Mercury 2
winner$0.375/M
Rank #33/163 · confidence 4
GPT-5.4
$2.50/M
Rank #133/163 · confidence 4
Mercury 2
winner$0.250/M
Rank #37/163 · confidence 4
GPT-5.4
10.6%
Rank #90/186 · confidence 4
Mercury 2
winner15.5%
Rank #69/186 · confidence 4
GPT-5.4
74.8%
Rank #96/187 · confidence 4
Mercury 2
winner77.0%
Rank #88/187 · confidence 4
GPT-5.4
winner47.1%
Rank #23/184 · confidence 4
Mercury 2
38.7%
Rank #83/184 · confidence 4
Latest completed audits from shared providers, with four safety and integrity score groups plus report links.
| Provider | GPT-5.4 | Mercury 2 |
|---|---|---|
| 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-5.4 | Mercury 2 |
|---|---|---|
5 tests | GPT-5.4 speed / latency N/A / N/A input / output No data | Mercury 2 speed / latency 618 tok/s / 847ms input / output No data |
0 tests | GPT-5.4 gpt-5-4 speed / latency N/A / N/A input / output $0.080/request | Mercury 2 mercury-2 speed / latency N/A / N/A input / output $0/request |
0 tests | GPT-5.4 speed / latency N/A / N/A input / output No data | Mercury 2 speed / latency N/A / N/A input / output No data |
0 tests | GPT-5.4 speed / latency N/A / N/A input / output No data | Mercury 2 speed / latency N/A / N/A input / output No data |
0 tests | GPT-5.4 speed / latency N/A / N/A input / output No data | Mercury 2 speed / latency N/A / N/A input / output No data |
Weighted outcome: GPT-5.4. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Input
Output
| Features | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning | Text inputText outputTool callingStructured outputsJSON modeReasoning |
|---|
