Like different generations of computer there are different generations of RAM. We will discuss one by one.
Static Random access memory or in short S RAM is a memory made of bi-stable transistor flip flop circuit. It stores data in bits. Data is loosed when power is removed. It doesn’t need to be refreshed like SD RAM. It far more faster than any other rams but it’s very expensive.
S RAM is typically used for more faster operations like cpu cache .
dynamic random access memory of in short D RAM is a storage device which stores each bit of Data using transistor and capacitor. Storage type is dynamic and needs to be electronically refreshed within every few milliseconds to compensate charge leaks from the capacitors.
The main advantages of DRAM are its simple design, speed and low cost. The main disadvantages of DRAM is it’s volatility and high power consumption compared to other options.
SD RAM or synchronized dynamic RAM is one type of RAM that synchronizes itself with the system clock. For being synchronized with processor it provides faster performance . It also supports 133 MHZ system bus cycling.
SD ram is rated in MHZ .This makes it easier to compare the BUS speed and the RAM chip speed. This types of Rams operates at 3.3 volts. It has 3 notches and 168 Pins.
DDR stands for double data rate. It’s one type of SD RAM. It transfers data on both the rising and falling edges of the clock signal.Hence doubles the data transfer rate.
Properties of DDR
DDR RAM enables twice data transfer each clock cycle. DDR, DDR2 and DDR3 are the different versions based on the same DDR technology. The design of all three RAMs are based on Synchronous Dynamic Random Access Memory. DDR is also known as double pumped, dual-pumped and double transition process.DDR or DDR1 falls in the category of first generation evolving from the SDRAM technology.
DDR RAM operates at 2.5 volt and 266 mhz to 400 mhz. It has 184 Pins. In next post we will discuss about DDR2 and DDR3 RAMs.