"The Kingston HyperX Beast 2x8GB kit is rated with two separate XMP profiles. The first is the top rated speed of 2133MHz with CL11 timings at 1.6v. The second rating is at 1600MHz with CL9 timings at 1.5v. Perhaps the reasoning behind the multiple XMP profiles is to target a consumer who has a lower cost PC now, but has plans on upgrading rather soon. "