You must use what the asus board supports and what they tell you to use:
8 x DIMM, Max. 64GB, DDR3 2133(O.C.)/2000(O.C.)/1866*/1600/1333/1066 MHz ECC, Non-ECC, Un-buffered Memory **
Quad Channel Memory Architecture
*For Registered Memory, Max. 256GB DDR3 1866/1600/1333/1066/800 MHz
** Refer to www.asus.com for the Memory QVL (Qualified Vendors Lists).