diff --git a/test/mjsunit/sparse-array-reverse.js b/test/mjsunit/sparse-array-reverse.js
index 9b9f32382e..45a6da4b5e 100644
--- a/test/mjsunit/sparse-array-reverse.js
+++ b/test/mjsunit/sparse-array-reverse.js
@@ -74,7 +74,15 @@ for (var iterations = 0; iterations < 20; iterations++) {
 
     var to_delete = [];
 
-    var a = new Array(size);
+    var a;
+    // Make sure we test both array-backed and hash-table backed
+    // arrays.
+    if (size < 1000) {
+      a = new Array(size);
+    } else {
+      a = new Array();
+      a.length = size;
+    }
 
     var expected = '';
     var expected_reversed = '';
diff --git a/test/mjsunit/try.js b/test/mjsunit/try.js
index a3f443376b..0bd78b4332 100644
--- a/test/mjsunit/try.js
+++ b/test/mjsunit/try.js
@@ -65,7 +65,7 @@ assertEquals(2, guard(function() { try { throw 2; } finally { var x = 12; } }));
 assertEquals(4, guard(function() { try { throw 3; } finally { throw 4; } }));
 
 (function () {
-  var iter = 10000000;
+  var iter = 1000000;
   for (var i = 1; i <= iter; i++) {
     try {
       if (i == iter) gc();