I have an old notebook which I use from time to time and would like to upgrade its RAM since it's really slow... It has two slots and only one is used, so I want to buy another RAM to put into the other slot.
Right now, the notebook has 1 x DDR2 PC2-4200 533MHz 512MB.
I have 2 options for the second slot:
a) DDR2 PC2-4200 533MHz 1024MB
b) DDR2 PC2-5400 667MHz 1024MB
Which one should I choose, so that the performance of the notebook will be the best possible?
If I mix two RAMs with different speeds, is the RAM with the higher speed gonna operate at a lower speed of the other RAM?