your mother board cannot support a clock speed of more than 1333 mhz buying 1600 mhz RAM for your mobo would be a waste. to upgrade your ram speed you need to upgrade your MoBo.
I think you are wrong. My current mother board is ASUS M5A 97, in ASUS website it is clearly written that it has :" 4 x DIMM, Max. 32GB, DDR3 2133(O.C.)/1866/1600/1333/1066 MHz ECC, Non-ECC, Un-buffered Memory, Dual Channel Memory Architecture"