A10-5800k and 2133mhz ram?

Solution
Officially, the 5800K supports up to DDR3-1866, but many motherboards will let you use DDR3-2133 or DDR3-2400 no problem. Stick with whatever your motherboard can handle. You should be able to Google the model number for the mobo, pull up the product page on the manufacturer's website, and it'll tell you right there how fast you can run your RAM.
Officially, the 5800K supports up to DDR3-1866, but many motherboards will let you use DDR3-2133 or DDR3-2400 no problem. Stick with whatever your motherboard can handle. You should be able to Google the model number for the mobo, pull up the product page on the manufacturer's website, and it'll tell you right there how fast you can run your RAM.
 
Solution