Intel | Difference between 1600mhz and 1800mhz

Does your motherboard support 1800Mhz RAM. If your motherboard doesn't the RAM will be down clocked to 1600mhz so you'll be wasting the money you paid extra for it. I've never seen any that speed listed on any motherboards, I've seen 1866Mhz but not 1800Mhz.