Hello! My question is in the title. I have an HP 6300 pro prebuilt computer and I'm pretty sure it came with 2+2gb of ram (I haven't opened it yet). I have a 4gb stick of the exact same speed lying around and wanted to put it in my pc so I'll have 8gb of ram. Can you help me? Will 2gb+2gb+4gb work as a total of 8gb ram on a mobo with 4 slots? Thanks in advance.