diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index 776c19efcb2..937f576e7d0 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -252,6 +252,8 @@ Bug Fixes
 * SOLR-5634: SolrJ GroupCommand.getNGroups returns null if group.format=simple
   and group.ngroups=true. (Artem Lukanin via shalin)
 
+* SOLR-5667: Performance problem when not using hdfs block cache. (Mark Miller)
+
 Optimizations
 ----------------------
 
diff --git a/solr/core/src/java/org/apache/solr/store/blockcache/CustomBufferedIndexInput.java b/solr/core/src/java/org/apache/solr/store/blockcache/CustomBufferedIndexInput.java
index 3e12b7022ed..be8f260b902 100644
--- a/solr/core/src/java/org/apache/solr/store/blockcache/CustomBufferedIndexInput.java
+++ b/solr/core/src/java/org/apache/solr/store/blockcache/CustomBufferedIndexInput.java
@@ -25,7 +25,7 @@ import org.apache.lucene.store.IndexOutput;
 
 public abstract class CustomBufferedIndexInput extends IndexInput {
   
-  public static final int BUFFER_SIZE = 1024;
+  public static final int BUFFER_SIZE = 32768;
   
   private int bufferSize = BUFFER_SIZE;