Have you looked at the documentation for the specific BIOS on that motherboard?
Although I've never actually done it, I was under the impression that overclocking the CPU and the memory timings were separate things. One should not affect the other. Is it your belief that impression is incorrect?
When you see ram rated above 1333 and even some 1333 sticks, the speed and timings are set via the XMP or Extreme Memory Profile. That is a standard that Intel developed a couple years ago to help ram and board manufacturers to work together to achieve compatibility. JEDEC was and is behind on approving the higher speed memory standards so the XMP standard provides standardization for ram outside the speed and timing spec approved by JEDEC. Now what this means is all ram normally has multiple profiles tattooed in the IC which include the Jedec Profile which is the default that the board detects and then the XMP profiles that the manufacturer programs. The board just has to recognize the profiles based on what the bios has listed for profiles. When you go into the bios, you should see the XMP profile settings under the Asus AI Tweaker under the AI Overclock Tuner. That is where you set the ram to the XMP Profile for that ram. Some ram sticks have more than 1 XMP profile but most of those are rated at lower latency than the standard CL 8 DDR3 1600. Keep in mind though that the voltage on some boards for the DRam controller does not always change correctly with the profile. You may have to change that manually.