Ranking cache evictions from a mid-depth layer beats SnapKV by 18 to 43 points
The KV cache stores past tokens' attention data, and eviction drops some to save memory, usually ranked by each layer's own attention. Across twenty-one models, long-context retrieval collapses when shallow layers do the ranking and peaks between 0.4 and 0.75 of depth. Scoring every cache from one chosen mid-depth layer beats per-head SnapKV by 18 to 43 points on five models up to 14B under tight budgets, with no extra forward pass.