Can I do this? 2x8gb + 2x4gb

[relvexlp]

I want to use my old 2x4gb ram kit with my 2x8gb like this, XXYY, X being the 8gb sticks, Y being the 4gb sticks. Would this work or could I break something doing this. They are both DDR3 if that matters.

 

[bmockeg]

Unless you are going to use over 16GB of RAM there is no benefit

 

[k1114]

Depends on the mobo for what slots they go in but they need to be in the right slots so you can have dual channel. The matching pair goes in the slots as if they were the only 2. Typically they are the same color but some mobos have all the same color ram slots. The manual would say. Manuals can be found online at the manufacturer's site. There isn't a chance of breaking anything so don't worry about that but compatibility could be an issue. Usually it works.