when i check on task manager > performance >memory speed say 1600mhz and when I check it on CMD using command "wmic memorychip get speed" speed say 1333mhz, however when i install CPU-Z > memory I can see the DRAM say 798.1mhz really dont know what is DRAM means so... is it 1333mhz or 1600mhz trying to buy extra 8gb ddr3 to match the same model for my current existing 8gb ram