Static RAM is a type of RAM that holds its data without
external refresh, for as long as power is supplied to the
circuit. This is contrasted to dynamic RAM (DRAM), which
must be refreshed many times per second in order to hold its
data contents. SRAMs are used for specific applications
within the PC, where their strengths outweigh their
weaknesses compared to DRAM:
• Simplicity: SRAMs don't require external refresh circuitry
or other work in order for them to keep their data intact.
• Speed: SRAM is faster than DRAM.
In contrast, SRAMs have the following weaknesses, compared
to DRAMs:
• Cost: SRAM is, byte for byte, several times more expensive
than DRAM.
• Size: SRAMs take up much more space than DRAMs (which is
part of why the cost is higher).