Random Access Memory (RAM)

Random Access Memory (RAM)

The kind of memory used for holding programs and data being executed is called random access memory or RAM. RAM differs from read-only memory (ROM) in that it can be both read and written. It is considered volatile storage because unlike ROM, the contents of RAM are lost when the power is turned off. RAM is also sometimes called read-write memory or RWM.
Obviously, RAM needs to be writable in order for it to do its job of holding programs and data that you are working on. The volatility of RAM also means that you risk losing what you are working on unless you save it frequently.
RAM is much faster than ROM is, due to the nature of how it stores information. This is why RAM is often used   to improve performance when executing BIOS code.
Dynamic RAM (DRAM)

Dynamic RAM is a type of RAM that only holds its data if it is continuously accessed by special logic called a refresh circuit. Many hundreds of times each second, this circuitry reads the contents of each memory cell, whether the memory cell is being used at that time by the computer or not. Due to the way in which the cells are constructed, the reading action itself refreshes the contents of the memory. If this is not done regularly, then the DRAM will lose its contents, even if it continues to have power supplied to it. This refreshing action is why the memory is called dynamic.

DDR RAM

Short for Double Data Rate, DDR is memory that was first introduced in  and has since been replaced by DDR utilizes both the rising and falling edge of the system clock that has the potential of doubling the speed of the memory. Today, the DDR technology is found on high end  and computer such as DDR-SDRAM.
RD RAM

Short for Rambus Dynamic Random Access Memory, RDRAM was developed by and first became available to computers in RDRAM is a memory technology that offers a 1.6 GB/s of theoretical memory bandwidth, and offers improved memory access at a slightly higher cost when compared to See our definition for further information about the RIMM socket After  contract with Rambus expired in 2001, Intel shifted its focus primarily to DDR SDRAM and today RDRAM is not often found in computers.