the 2133 is the limit intel puts out. at 1.25v you can get faster ram the memory controler can go up to 1.35v for ram voltage. the issue is if you go up to 3000 speed ram or faster and the cpu fails if you dont have the extra over clockers insurance intel can or might if they think the cpu was overclocked reject the rma. the skylake cpu is the first cpu with ddr4 and ddr3 ram controller. as newer kurby lake and the newer chipset come out that default speed should go up.