What Is SD RAM & DD RAM?

CPU speeds have increased faster than corresponding memory speeds

RAM stands for Random Access Memory and it refers to electronic memory that temporarily stores information in a computer. Dynamic RAM must be refreshed regularly to remain valid. SD RAM refers to Single Dynamic RAM, or Synchronous Dynamic RAM, while DD RAM refers to Double Dynamic Rate Synchronous RAM.

SD RAM

Synchronous Dynamic RAM uses a buffer and two banks of memory to synchronize with the system clock and balance width of the bus against the latency of the memory to improve bus utilization from the wide version of DRAM. It is delivered at a higher speed than what the narrow version offers.

DD RAM

DD RAM transfers data on both the rising and falling edge of the clock rate to deliver data at twice the speed of SD RAM. It produces a Double Data Rate or DDR. This is explained in full in John P. Abrams' "Information Technology: A Breadth First Approach" (See Resources).

History

Over the course of the fifteen years up to 2010, CPU speeds have increased faster than the corresponding memory speeds. As a result, technicians have attempted to compensate by adjusting the way computers access memory.

References

• Oklahoma City Community College: Computer Terms: RAM
• MIT: DRAM
• New Mexico State University: SDRAM

Resources

• Information Technology: A Breadth First Approach: John P. Abrahm