Android 4.3 on a Nexus 4 improves the benchmarks
most of the benchmarks for the device. A Nexus 4 running Android 4.2.2 did best the same device running Android 4.3 in CFBench -Native by a slight margin, but that was to be expected. CFBench - Java showed Android 4.3 improve results by over 500 points.Or rather, it seems to improve
Android 4.3 supports OpenGL 3.0, and that seems to have helped improve GLBenchmark 2.5 test results by 5 frames onscreen, and 6 frames for the off-screen test.
It is still far too early to know if these changes will make much real world difference, but the Dalvik Virtual Machine in Android 4.3 has also been optimized, which should provide noticeable performance boosts in most apps.