DRAM (Dynamic Random Access Memory) | what is DRAM? | Types of DRAM.

 DRAM (Dynamic Random Access Memory):

                                                                                                                                                          DRAM is a type of semiconductor memory where the word "Dynamic" indicates that it needs to be periodically refreshed to retain its data. it stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged' these two states are taken to represent the two values of a bit, conventionally called 0 and 1. in personal computers DRAMs are used as internal memory because of their simple structure that allows high storage and low cost as compared to SRAM . 

Types of DRAM:

                                            There are two types of DRAM 

• SDRAM
• DDR SDRAM 

 

1. SDRAM: 

                                     SDRAM stands for Synchronous Dynamic Random Access Memory. SDRAM is a high speed semiconductor memory. it is an improved form of the older DRAM (Dynamic Random Access memory)  SDRAM operates synchronously, which means that it operates in sync with the system data bus. Therefore, it can operate at much greater speeds than non-synchronous RAM.

            2. DDR SDRAM:

                                        DDR SDRAM (Double Data Rate SD RAM) is an improved SD RAM which allows a computer to transfer data at twice the speed. It has improved memory clock speed as compared to simple SD RAM. It reads or writes two consecutive words per clock cycle. there are many types of DDR SDRAMs used for computers today, including DDR1 RAM, DDR2 RAM and DDR3 RAM ranging in speed from 100 MHz to 2000 MHz. SDRAM comes in sizes of 512 MB to 4 GB for use in today's computers. 

DDR2 and DDR3 RAMs are used in today's computers. DDR2 reads and writes 4 words of data per clock cycle whereas DDR3 reads or writes 8 data words per clock cycle.