More information about the PNY memory stick is needed. You are more likely to get help if you provide the specs of the memory stick.
"4 x DIMM, Max. 32GB, DDR3 MHz Non-ECC, Un-buffered Memory Dual Channel Memory Architecture"
Source: http://www.asus.com/us/Motherboards/P8B75MCSM/specifications/
Does the PNY memory stick match those specs?