How to Select DRAM Modules
Image Creidt: Digi-Key | Innodisk | Wintec
DRAM modules are collections of dynamic random access memory (DRAM) chips assembled on circuit boards. DRAM chips are single-transistor dynamic memory cells that use capacitors to store each bit in a row-and-column addressable format. DRAM chips are a type of random access memory (RAM) that requires the capacitor to be continually charged or refreshed to retain data. Because a DRAM module is a dynamic memory device, it requires a power supply to maintain its data. In this way, DRAM modules use volatile memory. By contrast, static memory does not require the capacitor to be refreshed. Flash memory retains data regardless of the power supply.
DRAM modules are used in desktop and laptop computers as well as servers. Different types of DRAM modules are used in servers to augment memory capacity, in networking applications to increase bandwidth and ensure signal integrity, and in mobile applications to provide memory capacity with low power consumption and compact design. Different types of DRAM modules may selected for their specific characteristics. Examples include synchronous DRAM (SDRAM) modules, extended data out (EDO) modules, and fast page mode (FPM) modules.
The DRAM modules that are used in high-speed, low-power consumption applications are often synchronous DRAM modules. SDRAM modules come in a wide variety of memory and speed configurations and are used mainly in mainstream desktop or server applications. SDRAM modules have replaced older, obsolete extended data out (EDO) and fast page mode (FPM) modules.
Extended data out (EDO) and fast page mode (FPM) modules were both designed to increase the performance and speed of a computer system when reading or writing lines of data. The extended data out (EDO) memory chips also allowed the computer system to start up a new access call while outputting data from the previous call or cycle, effectively overlapping the memory access processes.