Ram Memory speed setting - on a ASRock FM2A88x Extreme6+ MB

[setdhook]

I just put together a desktop PC, using ASRock's FM2A88xExtreme6+ motherboard, A10-6800k AMD Quad Core Processor, and add some Vengeance 8GB DDR3-2133 (PC3-17000) CL11 Desktop Memory Module Kit (Two 4GBMemory Modules), and just noticed within the BIOS the speed of my added memory is showing up as 1333 Mhz speed, even though the bios is set to auto. I know that the speed needs to be changed, but I don't know much about changing the speed of the memory to 2133MHz, for the new memory. Can anyone point me to How and where to make this change to adjust the speed of my memory? Thanks in advance for your help.Ed