Corsair Vengeance DDR4 2666Mhz RAM not functioning correctly

[MarkedMetalTom]

Basically I'm pretty sure I am getting frame rate drops in my games because of my RAM configuration as this happened before and was fixed by changing my RAM settings in the BIOS. I have just upgraded from an i3-6100 to an i7-6700k I am using an ASRock extreme4 Z170 motherboard. I am loading the XMP profile fine and setting the correct frequency to DDR4-2666. This seems to be working fine, however in CPU-Z I am getting a max bandwitch reading of DDR4-2132 (1066Mhz). Any help on this issue would be much appreciated as I feel like I'm just going round in circles.

Just to confirm I have also flashed the BIOS to the most up-to-date version.

 

[Tradesman1]

Where in CPU-Z, need to look at the memory tab and take frequency x 2 (i.e. if at 1333 then you are running 2666, if it shows 1066 then you are at the mobos default of 2133