diff --git a/CHANGELOG.md b/CHANGELOG.md
index 989b96c5cf5..c2ef6edbd85 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -68,6 +68,7 @@
 * [ENHANCEMENT] Ruler: Adjust ruler frontend decoder to not wrap query error messages with execution prefix, this makes error responses consistent between internal and external ruler paths. #7741
 * [ENHANCEMENT] Distributor: Deduplicate metric metadata when converting PRW 2.0 requests. PRW 2.0 attaches metadata to every series, so a metric family was previously expanded into one `MetricMetadata` per series. #7760
 * [ENHANCEMENT] Update build image and Go version to 1.27.0. #7814
+* [ENHANCEMENT] Querier: Reduce merge iterator `BatchSize` from 12 to 8. #7823
 * [BUGFIX] Querier: Fix queryWithRetry and labelsWithRetry returning (nil, nil) on cancelled context by propagating ctx.Err(). #7370
 * [BUGFIX] Metrics Helper: Fix non-deterministic bucket order in merged histograms by sorting buckets after map iteration, matching Prometheus client library behavior. #7380
 * [BUGFIX] Distributor: Return HTTP 401 Unauthorized when tenant ID resolution fails in the Prometheus Remote Write 2.0 path. #7389
diff --git a/pkg/chunk/iterator.go b/pkg/chunk/iterator.go
index daf24d98099..05aa03b9cd5 100644
--- a/pkg/chunk/iterator.go
+++ b/pkg/chunk/iterator.go
@@ -30,7 +30,7 @@ type Iterator interface {
 
 // BatchSize is samples per batch; this was choose by benchmarking all sizes from
 // 1 to 128.
-const BatchSize = 12
+const BatchSize = 8
 
 // Batch is a sorted set of (timestamp, value) pairs. They are intended to be small,
 // and passed by value. Value can vary depending on the chunk value type.