||This article needs to be wikified. (April 2009)|
SRAM has many differences to Dynamic RAM (DRAM). The first of all is that for DRAMs, to keep the data that is stored from being lost, it has to be refreshed, by writing the same data to it over and over again with special circuitry, much like a pen that dispenses disappearing ink onto paper. The second difference is that SRAMs are also used for specific applications within the PC, where their strengths outweigh their weaknesses compared to DRAM.
Positive differences [change]
SRAM does not need to be refreshed, like words that have been written with a pencil on paper.
Changing Static RAM is also faster than DRAM.
Negative differences [change]
SRAM is more expensive than DRAM.
SRAMs take up much more space than DRAMs.
SRAM is created and manufactured in a way rather much like how processors are: A special light-and-shadow pattern is shone onto a sheet or wafer of silicon, then the parts of the silicon that had no light on them are dissolved away by a special acid. Each SRAM bit is composed of between four and six transistors, the parts that hold information, which is why SRAM takes up much more space compared to DRAM. To compare with SRAM, DRAM has only one transistor plus a capacitor (a sort of miniature rechargeable battery). SRAM chips are comprised of thousands or millions of identical cells. Because is much easier to make than a CPU, (a large die with a non-repetitive structure), RAM chips are far less expensive than processors.