SDRAM Full Form

What is the full form of SDRAM?

Synchronous Dynamic Random Access Memory is known as SDRAM. It synchronises with the system clock of the computer. Because of this, it is simple to manage quicker and SDRAM speed is measured in MHz rather than nanoseconds. The 16 Mb Samsung KM48SL2000 memory chip served as the first commercially available SDRAM. It was created in 1992 by Samsung Electronics utilising a Complementary metal–oxide–semiconductor(CMOS) fabrication technique, and it went into mass production in 1993. Due to its superior performance and quicker speed, SDRAM has mostly supplanted all other types of DRAM in modern computers by the year 2000.

This Story also Contains

1. What is the full form of SDRAM?
2. Generations of SDRAM
3. Failed Successors of SDRAM
4. Specifications of SDRAM

Generations of SDRAM

1. DDR SDRAM

DDR SDRAM, the first version of SDRAM, was created to give consumers access to additional bandwidth. This employs the same command, which is only acknowledged once each clock cycle, but reads or writes two data words. The rising and falling edges of the clock signal are used by the DDR interface to read and write data.

2. DDR2 SDRAM

The minimum read or write unit in DDR2 SDRAM is doubled once more to obtain four consecutive words, otherwise, it is quite comparable to DDR SDRAM. Additionally, the bus protocol was streamlined for improved performance. (The "burst termination" command, in particular, is eliminated.) Due to this, SDRAM's bus rate can quadruple while internal RAM operations' clock rates remain the same.

3. DDR3 SDRAM

This pattern is maintained by DDR3 SDRAM, which increases the minimum read or write unit to eight consecutive words. As a result, it is possible to double both the bandwidth and external bus rate without altering the internal processes' clock rate, just the width. The internal RAM array must execute 100-200 M fetches per second in order to maintain 800-1600 M transfers/s (both edges of the 400–800 MHz clock).

4. DDR4 SDRAM

Instead of increasing the internal prefetch width by two, DDR4 SDRAM uses the same 8n prefetch as DDR3. The operating voltage for DDR4 chips is 1.2V or less.

5. DDR5 SDRAM

Although DDR5 has not yet been made available, it aims to save power usage while increasing bandwidth over DDR4.

Failed Successors of SDRAM

1. Rambus DRAM (RDRAM)

A proprietary technique called RDRAM competes with DDR. The race for SDR DRAM was lost because of its comparatively high cost and poor performance (caused by high latencies and limited 16-bit data channels as opposed to DDR's 64-bit channels).

2. Synchronous-link DRAM (SLDRAM)

With SLDRAM, data skew is significantly reduced because the clock was generated by the data source (a SLDRAM chip in the case of a read operation) and transferred in the same direction as the data. Each command stated the DCLK pair it would employ in order to avoid the necessity of pausing whenever the source of DCLK changed.

3. Virtual Channel Memory (VCM) SDRAM

NEC created the proprietary kind of SDRAM known as VCM, however, it was made available as an open standard without a licence cost. Although the commands are different, it is pin-compatible with conventional SDRAM.

Due to VCM's lower cost than RDRAM, this technology presented a threat to RDRAM. Standard SDRAM and the Virtual Channel Memory (VCM) module are electrically and mechanically compatible, therefore only the memory controller's functionality determines whether either device may be supported.

Specifications of SDRAM

• The quick functioning speed of SDRAM contributes to its popularity. SDRAM access times range from 6 to 12 ns (nanoseconds).

• SDRAM only uses one edge of the clock, whereas DDR uses both edges.

• While DDR transfers data twice throughout each clock cycle, SDRAM delivers a single signal during each clock cycle.