There are different modules of server memory. Each module is formulated differently and works in a different way from the rest. These modules use either Single In-line Memory Module (SIMM) or Dual In-line Memory Module (DIMM). They include SDRAM, DDR SDRAM, DDR, DDR2, DDR3 and ECC. SIMM is the most basic module, followed by DIMM. This memory uses SDR (Single data rate) and has two notches. DDR SDRAM uses the double data rate (DDR). Other advanced modules using this technique are DDR2 and DDR3. SDRAM uses 168 pins while the more advanced DDR SDRAM uses 184 pins. It works by transferring data on the frequency of a clock signal. DDR2 is faster with 240 pins.

The most predominant memory modules in servers are ECC (Error Correction Codes). ECC Memory corrects errors that occur during data transmission or storage. ECC Memory uses Forward Error Codes to detect and rectify data errors. The size of ECC Memory should be proportional to the amount of RAM in the computer. The duration of operation also matters. When considering a memory upgrade, be sure to get the similar type of module so that it can fit into your system. If you do not have ECC, consider adding it to your system.