diff --git a/history.txt b/history.txt
index 44ba0f180..7d178bb17 100644
--- a/history.txt
+++ b/history.txt
@@ -1,3 +1,6 @@
+2012-07-15 zzz
+ * XORComparator: Reduce object churn (Ticket #658)
+
 2012-07-12 kytv
 * Translations from Transifex:
   - Add new Greek translation
diff --git a/router/java/src/net/i2p/router/networkdb/kademlia/XORComparator.java b/router/java/src/net/i2p/router/networkdb/kademlia/XORComparator.java
index bfd897f0a..9242103cd 100644
--- a/router/java/src/net/i2p/router/networkdb/kademlia/XORComparator.java
+++ b/router/java/src/net/i2p/router/networkdb/kademlia/XORComparator.java
@@ -6,22 +6,28 @@ import net.i2p.data.DataHelper;
 import net.i2p.data.Hash;
 
 /**
- * Help sort Hashes in relation to a base key using the XOR metric
- *
+ * Help sort Hashes in relation to a base key using the XOR metric.
+ * Warning - not thread safe.
  */
 class XORComparator implements Comparator<Hash> {
     private final byte[] _base;
+    private final byte[] _lx, _rx;
 
     /**
      * @param target key to compare distances with
      */
     public XORComparator(Hash target) {
         _base = target.getData();
+        _lx = new byte[Hash.HASH_LENGTH];
+        _rx = new byte[Hash.HASH_LENGTH];
     }
 
+    /**
+     * getData() of args must be non-null
+     */
     public int compare(Hash lhs, Hash rhs) {
-        byte lhsDelta[] = DataHelper.xor(lhs.getData(), _base);
-        byte rhsDelta[] = DataHelper.xor(rhs.getData(), _base);
-        return DataHelper.compareTo(lhsDelta, rhsDelta);
+        DataHelper.xor(lhs.getData(), 0, _base, 0, _lx, 0, Hash.HASH_LENGTH);
+        DataHelper.xor(rhs.getData(), 0, _base, 0, _rx, 0, Hash.HASH_LENGTH);
+        return DataHelper.compareTo(_lx, _rx);
     }
 }