Dual channel describes a technology that theoretically doubles data throughput from the memory to the memory controller.

Dual channel is the ability that some memory controllers have to expand the width of their data busses from 64 to 128 bits. Considering that everything remains the same (clock speed, ….), the memory maximum theoretical transfer rate is doubled by the use of this technique.

Think of it as a road intersection. The memory controller is the traffic light. In one direction you have a nice four lane road going through the light. One way goes to the CPU and the other goes around the board to where it is needed, such as the video card. There is another way to go, and that is to the memory. In single channel, this isn’t pretty. It’s a one lane street which needs to send information both directions. With dual channel it is a little bit easier. It could now be a two lane road, to send and receive at the same time.

Memory access i s When memory is read or written  , a specific procedure is used to control each access to memory, which consists of having the memory controller generate the correct signals to specify which memory location needs to be accessed, and then having the data show up on the data bus to be read by the processor or whatever other device requested it.

Memory controller is the part of the system that controls the memory byt generating the necessary signals to control the reading and writing of information from and to the memory, and interfaces the memory with the other major parts of the system. It can be a separate chip or integrated into another chip, such as on the  microprocessor.

Memory controllers contain the logic necessary to read and write dynamic random access memory (DRAM), and to “refresh” the DRAM by sending current through the entire device. Without constant refreshes, DRAM will lose the data written to it as the capacitors leak their charge within a fraction of a second.

DRAM VS RAM :

DRAM is dynamic in that, unlike static RAM , it needs to have its storage cells refreshed or given a new electronic charge every few milliseconds.  RAM does not need refreshing because it operates on the principle of moving current that is switched in one of two directions rather than a storage cell that holds a charge in place.  RAM is generally used for cache memory, which can be accessed more quickly than DRAM.

Only one transistor and a capacitor are required per bit, compared to four transistors in RAM. This allows DRAM to reach very high density. Unlike flash memory, it is volatile memory , since it loses its data when the power is off.

in brief :

Advantages: it’s compatible with just about everything. Disadvantates: it’s the slowest of the memory types currently available and because it isn’t in demand