diff --git a/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor.js b/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor.js
index e301d94..2a1e880 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor.js
@@ -32,6 +32,16 @@
     REMOVED: 'edit_a',
   };
 
+  /**
+   * The maximum size for an addition or removal chunk before it is broken down
+   * into a series of chunks that are this size at most.
+   *
+   * Note: The value of 70 is chosen so that it is larger than the default
+   * _asyncThreshold of 64, but feel free to tune this constant to your
+   * performance needs.
+   */
+  var MAX_GROUP_SIZE = 70;
+
   Polymer({
     is: 'gr-diff-processor',
 
@@ -328,13 +338,17 @@
 
         // If it isn't a common group, append it as-is and update line numbers.
         if (!content[i].ab) {
-          result.push(content[i]);
           if (content[i].a) {
             leftLineNum += content[i].a.length;
           }
           if (content[i].b) {
             rightLineNum += content[i].b.length;
           }
+
+          this._breakdownGroup(content[i]).forEach(function(group) {
+            result.push(group);
+          });
+
           continue;
         }
 
@@ -434,5 +448,48 @@
       }
       return normalized;
     },
+
+    /**
+     * If a group is an addition or a removal, break it down into smaller groups
+     * of that type using the MAX_GROUP_SIZE. If the group is a shared section
+     * or a delta it is returned as the single element of the result array.
+     * @param {!Object} A raw chunk from a diff response.
+     * @return {!Array<!Array<!Object>>}
+     */
+    _breakdownGroup: function(group) {
+      var key = null;
+      if (group.a && !group.b) {
+        key = 'a';
+      } else if (group.b && !group.a) {
+        key = 'b';
+      }
+
+      if (!key) { return [group]; }
+
+      return this._breakdown(group[key], MAX_GROUP_SIZE)
+        .map(function(subgroupLines) {
+          var subGroup = {};
+          subGroup[key] = subgroupLines;
+          return subGroup;
+        });
+    },
+
+    /**
+     * Given an array and a size, return an array of arrays where no inner array
+     * is larger than that size, preserving the original order.
+     * @param  {!Array<T>}
+     * @param  {number}
+     * @return {!Array<!Array<T>>}
+     * @template T
+     */
+    _breakdown: function(array, size) {
+      if (!array.length) { return []; }
+      if (array.length < size) { return [array]; }
+
+      var head = array.slice(0, array.length - size);
+      var tail = array.slice(array.length - size);
+
+      return this._breakdown(head, size).concat([tail])
+    },
   });
 })();
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor_test.html b/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor_test.html
index 4d890ea..9d687ac 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor_test.html
@@ -510,6 +510,69 @@
           assert.notOk(result[result.length - 1].afterNumber);
         });
       });
+
+      suite('_breakdown*', function() {
+        var sandbox;
+        setup(function() {
+          sandbox = sinon.sandbox.create();
+        });
+
+        teardown(function() {
+          sandbox.restore();
+        });
+
+        test('_breakdownGroup ignores shared groups', function() {
+          sandbox.stub(element, '_breakdown');
+          var chunk = {ab: ['blah', 'blah', 'blah']};
+          var result = element._breakdownGroup(chunk);
+          assert.deepEqual(result, [chunk]);
+          assert.isFalse(element._breakdown.called);
+        });
+
+        test('_breakdownGroup breaks down additions', function() {
+          sandbox.spy(element, '_breakdown');
+          var chunk = {b: ['blah', 'blah', 'blah']};
+          var result = element._breakdownGroup(chunk);
+          assert.deepEqual(result, [chunk]);
+          assert.isTrue(element._breakdown.called);
+        });
+
+        test('_breakdown common case', function() {
+          var array = 'Lorem ipsum dolor sit amet, suspendisse inceptos'
+              .split(' ');
+          var size = 3;
+
+          var result = element._breakdown(array, size);
+
+          result.forEach(function(subResult) {
+            assert.isAtMost(subResult.length, size);
+          });
+          var flattened = result
+              .reduce(function(a, b) { return a.concat(b); }, []);
+          assert.deepEqual(flattened, array);
+        });
+
+        test('_breakdown smaller than size', function() {
+          var array = 'Lorem ipsum dolor sit amet, suspendisse inceptos'
+              .split(' ');
+          var size = 10;
+          var expected = [array];
+
+          var result = element._breakdown(array, size);
+
+          assert.deepEqual(result, expected);
+        });
+
+        test('_breakdown empty', function() {
+          var array = [];
+          var size = 10;
+          var expected = [];
+
+          var result = element._breakdown(array, size);
+
+          assert.deepEqual(result, expected);
+        });
+      });
     });
   });
 </script>