Contextual AI Rerank v2 Instruct vs Zerank 2
Detailed comparison between Contextual AI Rerank v2 Instruct and Zerank 2. See which reranker best meets your accuracy and performance needs.
Model Comparison
Zerank 2 takes the lead.
Both Contextual AI Rerank v2 Instruct 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 183 higher ELO rating
- Zerank 2 is 3068ms faster on average
- Zerank 2 has a 16.0% higher win rate
Overview
Key metrics
ELO Rating
Overall ranking quality
Contextual AI Rerank v2 Instruct
Zerank 2
Win Rate
Head-to-head performance
Contextual AI Rerank v2 Instruct
Zerank 2
Accuracy (nDCG@10)
Ranking quality metric
Contextual AI Rerank v2 Instruct
Zerank 2
Average Latency
Response time
Contextual AI Rerank v2 Instruct
Zerank 2
Visual Performance Analysis
Performance
ELO Rating Comparison
Win/Loss/Tie Breakdown
Accuracy Across Datasets (nDCG@10)
Latency Distribution (ms)
Breakdown
How the models stack up
| Metric | Contextual AI Rerank v2 Instruct | Zerank 2 | Description |
|---|---|---|---|
| Overall Performance | |||
| ELO Rating | 1461 | 1644 | Overall ranking quality based on pairwise comparisons |
| Win Rate | 42.3% | 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 | 2025-09-12 | 2025-11-18 | Model release date |
| Accuracy Metrics | |||
| Avg nDCG@10 | 0.230 | 0.195 | Normalized discounted cumulative gain at position 10 |
| Performance Metrics | |||
| Avg Latency | 3333ms | 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 | Contextual AI Rerank v2 Instruct | Zerank 2 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| nDCG@5 | 0.510 | 0.491 | Ranking quality at top 5 results |
| nDCG@10 | 0.538 | 0.546 | Ranking quality at top 10 results |
| Recall@5 | 0.720 | 0.620 | % of relevant docs in top 5 |
| Recall@10 | 0.800 | 0.780 | % of relevant docs in top 10 |
| Latency Metrics | |||
| Mean | 3283ms | 233ms | Average response time |
| P50 | 3260ms | 228ms | 50th percentile (median) |
| P90 | 3885ms | 251ms | 90th percentile |
arguana
| Metric | Contextual AI Rerank v2 Instruct | Zerank 2 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| nDCG@5 | 0.525 | 0.283 | Ranking quality at top 5 results |
| nDCG@10 | 0.560 | 0.355 | Ranking quality at top 10 results |
| Recall@5 | 0.860 | 0.540 | % of relevant docs in top 5 |
| Recall@10 | 0.960 | 0.760 | % of relevant docs in top 10 |
| Latency Metrics | |||
| Mean | 3627ms | 280ms | Average response time |
| P50 | 3601ms | 278ms | 50th percentile (median) |
| P90 | 4037ms | 312ms | 90th percentile |
FiQa
| Metric | Contextual AI Rerank v2 Instruct | Zerank 2 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| nDCG@5 | 0.119 | 0.108 | Ranking quality at top 5 results |
| nDCG@10 | 0.125 | 0.119 | Ranking quality at top 10 results |
| Recall@5 | 0.123 | 0.098 | % of relevant docs in top 5 |
| Recall@10 | 0.135 | 0.130 | % of relevant docs in top 10 |
| Latency Metrics | |||
| Mean | 3283ms | 251ms | Average response time |
| P50 | 3209ms | 254ms | 50th percentile (median) |
| P90 | 3891ms | 270ms | 90th percentile |
business reports
| Metric | Contextual AI Rerank v2 Instruct | Zerank 2 | Description |
|---|---|---|---|
| Latency Metrics | |||
| Mean | 3231ms | 288ms | Average response time |
| P50 | 3129ms | 269ms | 50th percentile (median) |
| P90 | 3651ms | 367ms | 90th percentile |
PG
| Metric | Contextual AI Rerank v2 Instruct | Zerank 2 | Description |
|---|---|---|---|
| Latency Metrics | |||
| Mean | 3566ms | 293ms | Average response time |
| P50 | 3475ms | 281ms | 50th percentile (median) |
| P90 | 4148ms | 328ms | 90th percentile |
DBPedia
| Metric | Contextual AI Rerank v2 Instruct | Zerank 2 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| nDCG@5 | 0.158 | 0.138 | Ranking quality at top 5 results |
| nDCG@10 | 0.159 | 0.151 | Ranking quality at top 10 results |
| Recall@5 | 0.004 | 0.004 | % of relevant docs in top 5 |
| Recall@10 | 0.005 | 0.005 | % of relevant docs in top 10 |
| Latency Metrics | |||
| Mean | 3010ms | 247ms | Average response time |
| P50 | 3042ms | 242ms | 50th percentile (median) |
| P90 | 3283ms | 274ms | 90th percentile |
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