How to place my new memory stick [H55M-S2HP]

[Junioorr]

I have this motherboard and I just bought a new memory DDR3, and the old one which is also DDR3 they both at 1,333 GHZ but for some reason, the OS won't start if I have both of them plugged, Reading through forums and stuff, people say it has something to do with the placement in the slots.

can anyone help? need more details?

Thanks in advance.

[Vezina]

This is the AMD forum section.

I am not familiar with Intel stuff and I may never be ,but theoretically mixing RAM sticks/types from different manufacturers should be avoided.
The times when you were able to buy on stick of RAM of a specific size now and after some time to get another stick has ended.
With dual channel this never works as it either forces the RAM to be slower for compatibility reasons ,either the PC malfunctions.
So get the minimum amount you need when you buy the PC and if you upgrade buy a bigger kit and sell the one you ve had.They all want you to do that so they sell more hardware.

[AgentFXA]

Your board only got 2 ram slots - if both ram sticks boot fine (as single sticks) then there may be a problem with the slot - make sure sticks are seated firmly in their slot.

As above said it can be a compatibility problem too if ram is not exact same type/brand