Contextual AI Rerank v2 Instruct vs Zerank 1
Detailed comparison between Contextual AI Rerank v2 Instruct and Zerank 1. See which reranker best meets your accuracy and performance needs.
Model Comparison
Zerank 1 takes the lead.
Both Contextual AI Rerank v2 Instruct and Zerank 1 are powerful reranking models designed to improve retrieval quality in RAG applications. However, their performance characteristics differ in important ways.
Why Zerank 1:
- Zerank 1 has 92 higher ELO rating
- Contextual AI Rerank v2 Instruct delivers better accuracy (nDCG@10: 0.687 vs 0.676)
- Zerank 1 is 1885ms faster on average
- Zerank 1 has a 17.7% higher win rate
Overview
Key metrics
ELO Rating
Overall ranking quality
Contextual AI Rerank v2 Instruct
Zerank 1
Win Rate
Head-to-head performance
Contextual AI Rerank v2 Instruct
Zerank 1
Accuracy (nDCG@10)
Ranking quality metric
Contextual AI Rerank v2 Instruct
Zerank 1
Average Latency
Response time
Contextual AI Rerank v2 Instruct
Zerank 1
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 1 | Description |
|---|---|---|---|
| Overall Performance | |||
| ELO Rating | 1550 | 1642 | Overall ranking quality based on pairwise comparisons |
| Win Rate | 45.2% | 62.9% | 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 | 2025-07-10 | Model release date |
| Accuracy Metrics | |||
| Avg nDCG@10 | 0.687 | 0.676 | Normalized discounted cumulative gain at position 10 |
| Performance Metrics | |||
| Avg Latency | 3010ms | 1126ms | Average response time across all datasets |
Dataset Performance
By field
Comprehensive comparison of accuracy metrics (nDCG, Recall) and latency percentiles for each benchmark dataset.
FiQa
| Metric | Contextual AI Rerank v2 Instruct | Zerank 1 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| nDCG@5 | 0.119 | 0.115 | Ranking quality at top 5 results |
| nDCG@10 | 0.125 | 0.121 | Ranking quality at top 10 results |
| Recall@5 | 0.123 | 0.105 | % of relevant docs in top 5 |
| Recall@10 | 0.135 | 0.125 | % of relevant docs in top 10 |
| Latency Metrics | |||
| Mean | 2913ms | 995ms | Average response time |
| P50 | 2863ms | 992ms | 50th percentile (median) |
| P90 | 3289ms | 1124ms | 90th percentile |
SciFact
| Metric | Contextual AI Rerank v2 Instruct | Zerank 1 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| nDCG@5 | 0.867 | 0.863 | Ranking quality at top 5 results |
| nDCG@10 | 0.875 | 0.866 | Ranking quality at top 10 results |
| Recall@5 | 0.916 | 0.916 | % of relevant docs in top 5 |
| Recall@10 | 0.940 | 0.920 | % of relevant docs in top 10 |
| Latency Metrics | |||
| Mean | 3317ms | 1358ms | Average response time |
| P50 | 3198ms | 1287ms | 50th percentile (median) |
| P90 | 4004ms | 1571ms | 90th percentile |
PG
| Metric | Contextual AI Rerank v2 Instruct | Zerank 1 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| Latency Metrics | |||
| Mean | 3195ms | 1238ms | Average response time |
| P50 | 2951ms | 1217ms | 50th percentile (median) |
| P90 | 3781ms | 1316ms | 90th percentile |
business reports
| Metric | Contextual AI Rerank v2 Instruct | Zerank 1 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| Latency Metrics | |||
| Mean | 2883ms | 1072ms | Average response time |
| P50 | 2686ms | 1070ms | 50th percentile (median) |
| P90 | 3161ms | 1273ms | 90th percentile |
MSMARCO
| Metric | Contextual AI Rerank v2 Instruct | Zerank 1 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| nDCG@5 | 0.975 | 0.967 | Ranking quality at top 5 results |
| nDCG@10 | 0.975 | 0.971 | Ranking quality at top 10 results |
| Recall@5 | 1.000 | 0.987 | % of relevant docs in top 5 |
| Recall@10 | 1.000 | 0.993 | % of relevant docs in top 10 |
| Latency Metrics | |||
| Mean | 2952ms | 1005ms | Average response time |
| P50 | 2853ms | 993ms | 50th percentile (median) |
| P90 | 3398ms | 1071ms | 90th percentile |
DBPedia
| Metric | Contextual AI Rerank v2 Instruct | Zerank 1 | Description |
|---|---|---|---|
| Accuracy Metrics | |||
| nDCG@5 | 0.734 | 0.715 | Ranking quality at top 5 results |
| nDCG@10 | 0.772 | 0.747 | Ranking quality at top 10 results |
| Recall@5 | 0.067 | 0.064 | % of relevant docs in top 5 |
| Recall@10 | 0.108 | 0.103 | % of relevant docs in top 10 |
| Latency Metrics | |||
| Mean | 2803ms | 1085ms | Average response time |
| P50 | 2786ms | 1036ms | 50th percentile (median) |
| P90 | 3138ms | 1243ms | 90th percentile |
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