I had 2x4gb ddr4 ram on My pc and i decided to buy other 2x4gb ram so i would have 16gb ram.the new rams are exactly the same as the old so they should be compatible but when i try to start my pc the dram light comes on. I tries to clear the cmos with the battery removing. But still didnt Help. The pc works again if i only use 2 ram sticks but dont work with all 4. The ram is corsair vengeance lpx 4gb ddr4 2133mhz and my mobo is msi b150m mortar. I hope that someone Will Help me with this problem