There are different types of memory. Each type can use any of the many memory modules. Each module in turn uses a different technology. It is important to know the technology used by your memory module when considering a memory upgrade. One such technology is DRAM Dynamic Random Access Memory, the most common RAM in use today. Its capacity is measured in access time and storage capacity - the lower the speed; the faster the memory. Unfortunately, it holds data for a short period of time. For this reason it should be refreshed every now and then

Fast Page Mode (FPM) works in a similar mode as DRAM but is faster. Extended Data Out (EDO) gives better performance than the above and requires only one wait state. Burst Extended Data Out (BEDO) is better than EDO and requires no wait state. SDRAM (Static RAM) is more advanced, working in sync with the CPU. It’s also faster. The only setback is that it is slightly expensive. DDR SDRAM (Double Data Rate Synchronous DRAM) enables transfers on both the up and down sides of the clock. Confirm whether you can interchange modules based on technology when upgrading. Also, consider buying a custom USB for backing up.