My old PC was extremely slow and finally, we have no choice but to get ourselves a new desktop recently. I was told that the machine is too old for any memory upgrade because that PC is over five years old.
However, if your PC is fairly new and you wish to increase the memory, you may want to learn something from this website. IBM memory is where you can find out how to upgrade your PC. You just need to choose your model and they will do the rest for you. Give it a try if you wish to improve your PC performance.