The old ram is unplugged and then the new one is plugged in. RAM can be bought at many electronics retailers. The new ram is unboxed and the cords are pulled out of the plastic shell and screws removed from the chassis.
Different types of ram:
SDRAM – Synchronous Dynamic Random Access Memory
DDR – Dual-channel Double Data Rate or dual double data rate
Dual-Channel means you replace 2 sticks together with 4 GB total.
SO DIMMs contain 168 pins on either side with gold connections for superior conductivity? Their parallel interfaces transfer data in both directions simultaneously while a serial interface passes information in a single direction only, which takes longer to transfer more bits.