Kingston has several different HyperX 4GB DDR3 1600MHz memory kits.
Please post a link to your exact memory kit's specifications on the Kingston web site.
How many modules are you using?
It will help if you post a Cpu-z SPD screen-shot for your memory.
Sample Cpu-z SPD screen-shot on the web for Kingston HyperX Genesis DDR3-1600 CAS 9: