I found a little info on that motherboard that should help.

  • Your Dell XPSmaximum RAMcapacity: 12GB
  • The XPS 730x has 3 memory slots or sockets
  • This XPS module upgrade PIN count is: 240-PIN
  • The memory speed is: DDR3 1066MHz, PC3-8500
  • The PC DIMM type for your XPS 730x is: UDIMM, Unbuffered DIMM, Unregistered DIMM