what is SDRAM?

SDRAM (synchronous DRAM):

• SDRAM (synchronous dynamic random access memory)
• that are synchronized with the clock speed that the microprocessor is optimized
• This tends to increase the number of instructions that the processor can perform in a given time.
• The speed of SDRAM is rated in MHz rather than in nanoseconds (ns). 
• This makes it easier to compare the bus speed and the RAM chip speed
• You can convert the RAM clock speed to nanoseconds by dividing the chip speed into 1 billion ns (which is one second)
• For example, an 83 MHz RAM would be equivalent to 12 ns.