Memory Type: DDR2 PC2-5300, DDR2 (ECC)
Maximum Memory: 64GB
Installed in pairs of modules.The system supports a maximum of four riser cards. Each riser card has 4 memory sockets configured as 2 banks of 2 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