NoobsPH

Hello im new here, and i have a problem.I brought a new ram called vaseky 4gb ram 1600mhz.The problem is when i turn on the computer the bios showing only 4gb when my ram is 1x2gb/1x4gb.When i removed the 2 gb the computer wont boot.I removed the vaseky 4gb ram in the motherboard and i put the 2gb ram and a 4gb samsung brand the computer boot and the bios show 6gb of ram correctly.My motherboard is a biostar hifi a70u3p ver.6.3