I have an asrock z170pro4s that was working fine with my ddr4 ram @ 2.998mhz using an i5 6500. I never used the sky overclocking on the board for non K cpus and updated the bios because of random freezing when i was in the bios. I had the ram speed set by the intel xmp profile as well. After updating to the latest bios which specifically states it removes sky overclocking i cant get my ram running at 2.998mhz it only works at the minimum 2133mhz. i am using Corsair memory rated at 3000mhz by the way. Using xmp or just manually setting the ram speed higher than 2133mhz prevents my computer from booting, cant even enter the bios i have to reset the cmos to get back into the bios.