So my question is can I put a single stick of RAM in my Dual channel supported motherboard which is a ASROCK 870 extreme3. The reason for this is I had to send in my old memory which was Mushkin Silverline DDR3 1333 and I wanted to borrow a stick of the same type of ram out of my brothers computer for now until my new ram comes. I wanted to know if it would mess anything up with our computers having a single stick in a dual channel motherboard I figured it might be backwards compatible or something?
Yes, you can run your mobo with just one stick; you will not damage either computer by using a single stick of RAM and RAM is not backward compatible. You will not be able to install DDR2 into DDR3, or vice versa. While both DDR2 and DDR3 are both 240-pin, the gap is in a different place. This done to prevent accidental installation of DDR2 into DDR3 or DDR3 into DDR2.