I have a HP dm4-1165dx laptop (11 years old) and I am planning on upgrading from 4GB of RAM to 8GB. Should I get 2 new 4GB sticks or would it be okay if I used a new RAM stick with the stick that is 11 years old? (I should mention that if I were to combine old and new RAM, the brand/model of the new stick would be the same as the old one.)
Ram from the same vendor and part number can be made up of differing manufacturing components over time. Some motherboards, especially old models can be very sensitive to this. Though the chance of success is very high. My advice is to try to combine your old RAM with a new stick and if that doesn't work - return it to the store and buy a kit. It will certainly suit.