Cohere Rerank 4 Fast vs Zerank 2
Detailed comparison between Cohere Rerank 4 Fast and Zerank 2. See which reranker best meets your accuracy and performance needs.
Model Comparison
Zerank 2 takes the lead.
Both Cohere Rerank 4 Fast and Zerank 2 are powerful reranking models designed to improve retrieval quality in RAG applications. However, their performance characteristics differ in important ways.
Why Zerank 2:
- Zerank 2 has 137 higher ELO rating
- Zerank 2 delivers better accuracy (nDCG@10: 0.079 vs 0.000)
- Zerank 2 is 181ms faster on average
- Zerank 2 has a 9.0% higher win rate
Overview
Key metrics
ELO Rating
Overall ranking quality
Cohere Rerank 4 Fast
Zerank 2
Win Rate
Head-to-head performance
Cohere Rerank 4 Fast
Zerank 2
Accuracy (nDCG@10)
Ranking quality metric
Cohere Rerank 4 Fast
Zerank 2
Average Latency
Response time
Cohere Rerank 4 Fast
Zerank 2
Visual Performance Analysis
Performance
ELO Rating Comparison
Win/Loss/Tie Breakdown
Latency Distribution (ms)
Breakdown
How the models stack up
| Metric | Cohere Rerank 4 Fast | Zerank 2 | Description |
|---|---|---|---|
| Overall Performance | |||
| ELO Rating | 1506 | 1644 | Overall ranking quality based on pairwise comparisons |
| Win Rate | 49.3% | 58.3% | Percentage of comparisons won against other models |
| Pricing & Availability | |||
| Price per 1M tokens | $0.050 | $0.025 | Cost per million tokens processed |
| Release Date | 2025-12-11 | 2025-11-18 | Model release date |
| Accuracy Metrics | |||
| Avg nDCG@10 | N/A | 0.079 | Normalized discounted cumulative gain at position 10 |
| Performance Metrics | |||
| Avg Latency | 447ms | 265ms | Average response time across all datasets |
Dataset Performance
By field
Comprehensive comparison of accuracy metrics (nDCG, Recall) and latency percentiles for each benchmark dataset.
MSMARCO
| Metric | Cohere Rerank 4 Fast | Zerank 2 | Description |
|---|---|---|---|
| Latency Metrics | |||
| Mean | 403ms | 233ms | Average response time |
| P50 | 382ms | 228ms | 50th percentile (median) |
| P90 | 486ms | 251ms | 90th percentile |
arguana
| Metric | Cohere Rerank 4 Fast | Zerank 2 | Description |
|---|---|---|---|
| Latency Metrics | |||
| Mean | 574ms | 280ms | Average response time |
| P50 | 562ms | 278ms | 50th percentile (median) |
| P90 | 728ms | 312ms | 90th percentile |
FiQa
| Metric | Cohere Rerank 4 Fast | Zerank 2 | Description |
|---|---|---|---|
| Latency Metrics | |||
| Mean | 485ms | 251ms | Average response time |
| P50 | 459ms | 254ms | 50th percentile (median) |
| P90 | 624ms | 270ms | 90th percentile |
business reports
| Metric | Cohere Rerank 4 Fast | Zerank 2 | Description |
|---|---|---|---|
| Latency Metrics | |||
| Mean | 428ms | 288ms | Average response time |
| P50 | 408ms | 269ms | 50th percentile (median) |
| P90 | 550ms | 367ms | 90th percentile |
PG
| Metric | Cohere Rerank 4 Fast | Zerank 2 | Description |
|---|---|---|---|
| Latency Metrics | |||
| Mean | 492ms | 293ms | Average response time |
| P50 | 439ms | 281ms | 50th percentile (median) |
| P90 | 650ms | 328ms | 90th percentile |
DBPedia
| Metric | Cohere Rerank 4 Fast | Zerank 2 | Description |
|---|---|---|---|
| Latency Metrics | |||
| Mean | 297ms | 247ms | Average response time |
| P50 | 297ms | 242ms | 50th percentile (median) |
| P90 | 309ms | 274ms | 90th percentile |
Explore More
Compare more rerankers
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