Memory Type: DDR PC3200, DDR (ECC)
Maximum Memory: 4GB
Unless only one 256-MB memory module is installed, the modules must be installed in identical pairs. If you want 512MB total, you will need to populate by using two identical 256MB modules.Although the memory can be installed one module at a time, the best performance comes from using matched pairs of modules.
How much memory your Windows OS will recognize depends on which version of Windows you are running. 32-bit versions of Windows will see (and utilize) only 3GB or 3.5GB. To utilize more memory, install a 64-bit version of your OS. More information about OS memory maximums can be found here.
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.
video - installing memory