Now a days we use different types of RAM (Random Access Memory). But in general RAMs (Random Access Memory) are three types. We saw the different types of RAM, which are we can take under the category of these types RAM which I am going to tell you about.
- SRAM (Static Random Access Memory).
- DRAM (Dynamic Random Access Memory).
- SDRAM (Synchronous Dynamic Random Access Memory).
One can arise in your mind that What is RAM ? We already write an article about the Concept of Ram. You can read that.
Read also: Definition of RAM.
SRAM (Static Random Access Memory)
Used primarily to create to create CPU’s speed-sensitive cache, Static Random Access Memory used multiple transistors for each memory cell. It does not have a capacitor in each cell.
Each bit of memory is held by a flip-flop memory which takes four to six transactions besides some wiring. SRAM is not required to be refreshed which makes it significantly fast. As compared to DRAM, SRAM has more parts and therefore it consumes a lot more space on a chip. With less memory available per chip, the SRAM becomes costlier.
DRAM (Dynamic Random Access Memory)
Dynamic Random Access memory needs to be refreshed consistently and contains memory cells with a paired transistor. In order to active the transistor at each bit in the column, DRAM sends a charge through the appropriate column (CAS).
The level of change is determined by the sense-amplifier while reading. If the level of charge exceeds fifty percent, it is read as a 1 whereas if the charge is below fifty percent it is read as a 0. For dynamic memory to work, Either the CPU or the memory controller recharges all the capacitors before they are discharge to zero. To ensure this the memory is read and written back which if referred to as referred to as refresh operation. DRAM is required to be refreshed dynamically all the time otherwise it will lose the information. The refreshing operation consumes a lot of time and causes the memory to slow down.
The refresh sequence id tracked by the counter after determining the other in which the rows have been accessed. The time required to do the entire task is expressed only in nanoseconds. A memory chip rating of 100 nanoseconds will mean then it take 100 nanoseconds to each cell completely and recharge them.
Memory cells have a support infrastructure of other specialized of other specialized circuits so that information can be put in and retrieved from them. These circuits identify each and column, keep track of the refresh sequence, read and restore the signal from a cell and tell whether it should take a charge or not.
SDRAM (Synchronous Dynamic Random Access Memory)
Synchronous Dynamic Random Access Memory enhance the system’s performance by utilizing the burst mode concept. With maximum transfer rate to L2 cache of 528 mbps, SDRAM stays on the row that contains the requested bit and moves quickly through the columns to read each bit as it moves on.
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