Synchronous DRAM

Synchronous DRAM


(Synchronous DRAM) The type of dynamic RAM memory chip that has been widely used since the mid-1990s. SDRAM eliminated wait states by dividing the chip into two cell blocks and interleaving data between them. While a bit in one block is accessed, a bit in the other is prepared for access. See dynamic RAM.

DDR (Double Data Rate)
In 2000, DDR SDRAM doubled the data transfer rate by using both the rising and falling edges of the clock cycle. The data rate of each DDR generation is faster than the previous with a six-fold increase from DDR1 to DDR4. In addition, less power is required (see table below). In order to prevent inserting the wrong DDR into the motherboard, DDR memory modules are keyed differently (for details, see memory module).

Chipsets on the motherboard may support one, two or four memory channels (triple channel has since come and gone). For example, mainstream motherboards support dual channel, which is why memory modules are generally installed in pairs. While data are being read or written to one memory module, the second module is being prepared for reading or writing. High-end motherboards support quad channel. Following are the most popular module speeds for each SDRAM generation. See GDDR.

        Clock    Transfer        DIMM        Speed      Rate         Module DDR    (MHz)     (MT/s)    (V)  Pins

 DDR5 1600-3200  3200-6400  1.1  288
 DDR4  800-1600  1600-3200  1.2  284
 DDR3  400-1200   800-2400  1.5  240
 DDR2  200-533    533-800   1.8  240
 DDR   100-200    200-400   2.5  184
 SDRAM  66-133     66-133   3.3  168

Matched Slots for Dual Channel
This motherboard uses colored sockets so that module pairs are inserted properly. It supports three pairs (one orange and two lavender). (Image courtesy of Giga-byte Technology Company Ltd.,

A Little Nostalgia
These 12 bits of magnetic core memory from the Whirlwind computer of the early 1950s take up about a quarter of a square inch. Today, that much space holds billions of bits. (Image courtesy of The MITRE Corporation Archives.)
References in periodicals archive ?
Emerging volatile next generation memory technologies included in the report are Static Random Access Memory (SRAM) and Dynamic Random Access Memory (DRAM), which include Synchronous DRAM (SDRAM), mobile DRAM, and other emerging DRAM technologies.
This is possible because the device integrates a low voltage Double Data Rate III Synchronous DRAM. Usually installed for a Notebook PC, this helps in 8 percent power saving than the regular DRAM.The Mini PC is also unnaturally stealthy in its operations and one doesn't hear the usual fan-noise that is associated with PCs.
ProMOS, the world's eighth-largest dynamic access random memory chip maker, will manufacture double data rate 3 synchronous DRAM chips, or DDR3 SDRAM chips, at a rate of 35,000 300-millimeter silicon wafers a month under the Elpida brand, it said.
The Model T5372 Memory Tester reduces wafer test time for dynamic random-access memory (DRAM), synchronous DRAM (SDRAM), double-data-rate (DDR)-SDRAM, flash-memory, and other general-purpose memory chips as well as for multichip packages and other specially packaged memories.
The latest investment is aimed at helping Elpida accelerate production of DDR2 SDRAM (double-date rate synchronous DRAM) chips for use with a new Intel microprocessor targeted at high-performance PCs and servers.
Micron Technology, Inc., has demonstrated the industry's first 1Gigabit (Gb) Double Data Rate (DDR) synchronous DRAM (SDRAM) components manufactured on 0.11 micron process technology.
In addition, the impending industry change from standard synchronous DRAM chips to faster double data rate (DDR) chips may have led some manufacturers to launch a ``fire sale'' of old product in October.
Samsung Electronics has developed a 64Mb double-data-rate synchronous DRAM device that operates at up to 300MHz.
Infineon Technologies (DAX/NYSE: IFX) has reinforced its leading position in high-performance memory technologies by introducing the fastest version of its 128-Mbit synchronous DRAM (SDRAM), and the related unbuffered modules.
This is possible to do using today's very fast SRAM or synchronous DRAM memory.
The LT has a 4.3GB hard drive that is shock-mounted, along with 64MB of synchronous DRAM.

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