Memory Type: DDR3 PC3-8500, DDR3 (non-ECC)
Maximum Memory: 4GB
System utilizes either the 2.0GHz or 2.4GHz Intel Core 2 Duo processor and the nVidia GeForce 9400M graphics processor.
Memory or DRAM is the "working" memory of the computer. It's used to store data for programs (sequences of instructions) on a temporary basis.
Install Guide for your:
MacBook (13-inch, Aluminum, Late 2008)
video - installing memory