Check the motherboard's documentation for what RAM has been tested and validated with the board. This is typically posted and updated regularly on Asus's website if you go to the board's product page.
Note that this list is not an exhaustive list of what *will* work with the board, but only a list of what has been tested and validated as functioning properly with the board. RAM manufacturers like Crucial also have web-based tools for selecting what Ram will work with your board.