Data points: 135
Model compare
The readout for DeepSeek V4 Flash and GPT-5.1, before the detailed comparison sheet.
Weighted outcome: GPT-5.1. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Decision read
GPT-5.1
GPT-5.1 has the higher weighted result; Model A / B score 34.7 to 65.3.
Evidence depth
135 data points
Includes 25 benchmark rows, 4 audit samples, and 9 provider examples.
Selection signal
Start with GPT-5.1
The charts below split 38 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 DeepSeek V4 Flash and GPT-5.1: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Model compare | DeepSeek V4 Flash | GPT-5.1 |
|---|---|---|
| Overall leader | Contender | Leading |
| Weighted overall score | 34.7 pts | 65.3 pts |
| Benchmark category leads | 2 categories | 4 categories |
| Operational advantages | Cheapest input price, Provider coverage | Average speed, First-token latency, Free providers |
| Context window | 1.0M tokens | 400K tokens |
| Max output | 65.5K tokens | 128K tokens |
| Modalities | Input Text Output Text | Input Image |
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 | DeepSeek V4 Flash | GPT-5.1 |
|---|---|---|
| Developer | DeepSeek | OpenAI |
| Released | Apr 2026 | Nov 2025 |
| Parameters | No data | No data |
| Tokenizer | DeepSeek | GPT |
| Knowledge cutoff | No data | No data |
| OpenRouter ID | deepseek/deepseek-v4-flash | openai/gpt-5.1 |
| References | No data | No data |
This report only uses LMSpeed data for DeepSeek V4 Flash and GPT-5.1: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
DeepSeek V4 Flash
DeepSeek V4 Flash is stronger in benchmark categories (Agents, Instruction following) and operational dimensions (Cheapest input price, Provider coverage).
GPT-5.1
GPT-5.1 is stronger in benchmark categories (Coding, Reasoning, Knowledge, Math) and operational dimensions (Average speed, First-token latency, Free providers).
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
DeepSeek V4 Flash
45.8
Avg. score
GPT-5.1
52.1
DeepSeek V4 Flash leads by 0.3
GPT-5.1 leads by 4.9
GPT-5.1 leads by 1.2
GPT-5.1 leads by 15.1
GPT-5.1 leads by 17.4
No data
No data
DeepSeek V4 Flash leads by 0.3
Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.
DeepSeek V4 Flash
winner58.0
Rank #39/83 · confidence 2 · eval date 2026-04-24
GPT-5.1
56.0
Rank #44/83 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner$0.280/M
Rank #6/162 · confidence 4
GPT-5.1
$10.00/M
Rank #121/162 · confidence 4
DeepSeek V4 Flash
winner$0.175/M
Rank #11/162 · confidence 4
GPT-5.1
$3.44/M
Rank #118/162 · confidence 4
DeepSeek V4 Flash
winner$0.140/M
Rank #17/162 · confidence 4
GPT-5.1
$1.25/M
Rank #108/162 · confidence 4
DeepSeek V4 Flash
63.0
Rank #53/89 · confidence 2 · eval date 2026-04-24
GPT-5.1
winner75.0
Rank #3/89 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
86.2%
Rank #15/125 · confidence 2 · eval date 2026-04-24
GPT-5.1
winner87.0%
Rank #12/125 · confidence 4
DeepSeek V4 Flash
winner7.1
Rank #29/73 · confidence 2 · eval date 2026-04-24
GPT-5.1
4.9
Rank #34/73 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
86.7%
Rank #35/187 · confidence 4
GPT-5.1
winner87.3%
Rank #32/187 · confidence 4
DeepSeek V4 Flash
winner27.8%
Rank #35/186 · confidence 4
GPT-5.1
26.5%
Rank #39/186 · confidence 4
DeepSeek V4 Flash
winner56.2
Rank #22/58 · confidence 2 · eval date 2026-04-24
GPT-5.1
49.4
Rank #32/58 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner44.9
Rank #41/96 · confidence 2 · eval date 2026-04-24
GPT-5.1
43.3
Rank #45/96 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
42.0%
Rank #51/184 · confidence 4
GPT-5.1
winner43.3%
Rank #41/184 · confidence 4
DeepSeek V4 Flash
winner81.6
Rank #6/56 · confidence 2 · eval date 2026-04-24
GPT-5.1
49.9
Rank #30/56 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner95.8
Rank #1/90 · confidence 2 · eval date 2026-04-24
GPT-5.1
51.3
Rank #66/90 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner40.3
Rank #26/99 · confidence 2 · eval date 2026-04-24
GPT-5.1
36.9
Rank #42/99 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner89.4
Rank #27/96 · confidence 2 · eval date 2026-04-24
GPT-5.1
87.3
Rank #36/96 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner32.1
Rank #27/96 · confidence 2 · eval date 2026-04-24
GPT-5.1
26.5
Rank #39/96 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
37.2
Rank #33/90 · confidence 2 · eval date 2026-04-24
GPT-5.1
winner37.6
Rank #31/90 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner1240.0
Rank #32/65 · confidence 2 · eval date 2026-04-24
GPT-5.1
1220.0
Rank #37/65 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner79.2
Rank #5/86 · confidence 2 · eval date 2026-04-24
GPT-5.1
72.9
Rank #30/86 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner31.1
Rank #15/54 · confidence 2 · eval date 2026-04-24
GPT-5.1
21.0
Rank #36/54 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner54.4
Rank #18/50 · confidence 2 · eval date 2026-04-24
GPT-5.1
41.2
Rank #35/50 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner95.0
Rank #19/84 · confidence 2 · eval date 2026-04-24
GPT-5.1
81.9
Rank #52/84 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner1189.0
Rank #21/54 · confidence 2 · eval date 2026-04-24
GPT-5.1
987.0
Rank #35/54 · confidence 1 · eval date 2025-11-13
DeepSeek V4 Flash
winner34.4
Rank #22/50 · confidence 2 · eval date 2026-04-24
GPT-5.1
24.4
Rank #35/50 · confidence 1 · eval date 2025-11-13
Latest completed audits from shared providers, with four safety and integrity score groups plus report links.
| Provider | DeepSeek V4 Flash | GPT-5.1 |
|---|---|---|
Winner: DeepSeek V4 Flash | DeepSeek V4 Flash deepseek-v4-flash Audit score 92 1008484100 | GPT-5.1 gpt-5.1-chat-latest No audit yet |
Winner: DeepSeek V4 Flash | DeepSeek V4 Flash deepseek-v4-flash Audit score 92 10068100100 | GPT-5.1 gpt-5.1 No audit yet |
Winner: DeepSeek V4 Flash | DeepSeek V4 Flash deepseek-v4-flash Audit score 85 846886100 | GPT-5.1 gpt-5.1-chat-latest No audit yet |
Winner: DeepSeek V4 Flash | DeepSeek V4 Flash deepseek-v4-flash Audit score 84 787584100 | GPT-5.1 gpt-5.1 No audit yet |
Speed aggregates and input/output pricing share each provider row for real API selection and migration cost checks.
| Provider | DeepSeek V4 Flash | GPT-5.1 |
|---|---|---|
65 tests | DeepSeek V4 Flash speed / latency 58 tok/s / 29936ms input / output No data | GPT-5.1 speed / latency N/A / N/A input / output No data |
20 tests | DeepSeek V4 Flash speed / latency 83 tok/s / 5114ms input / output No data | GPT-5.1 speed / latency N/A / N/A input / output No data |
10 tests | DeepSeek V4 Flash speed / latency 42 tok/s / 3076ms input / output No data | GPT-5.1 speed / latency N/A / N/A input / output No data |
10 tests | DeepSeek V4 Flash speed / latency 86 tok/s / 4077ms input / output No data | GPT-5.1 speed / latency N/A / N/A input / output No data |
10 tests | DeepSeek V4 Flash speed / latency 143 tok/s / 1761ms input / output No data | GPT-5.1 speed / latency N/A / N/A input / output No data |
DeepSeek V4 Flash deepseek-v4-flash speed / latency No data input / output $0/M/$0/M | GPT-5.1 gpt-5.1 speed / latency No data input / output $0.086/M | |
DeepSeek V4 Flash deepseek-v4-flash speed / latency No data input / output $0/request | GPT-5.1 gpt-5.1 speed / latency No data input / output $0/request | |
DeepSeek V4 Flash deepseek-v4-flash speed / latency No data input / output $0/request | GPT-5.1 gpt-5-1 speed / latency No data input / output $0.040/request | |
DeepSeek V4 Flash deepseek-v4-flash speed / latency No data input / output $0.0000014/M/$0.0000028/M | GPT-5.1 gpt-5.1 speed / latency No data input / output $1.88/M |
Weighted outcome: GPT-5.1. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Output
| Features | Text inputText outputTool callingStructured outputsJSON modeReasoning | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning |
|---|
