Types of DRAM
Types of DRAM
Fast Page Mode DRAM (FPMDRAM)
Standard DRAM is accessed through a technique called paging. Paging facilitates faster entrance to all the data inside a given row of memory by observing the row address the same and altering only the column. Memory that uses this modus operandi is called Page Mode or Fast Page Mode memory. This method was accepted on 32-bit wide memory systems on 486 processors but fell out of support on Pentiums because of their 64-bit wide memory widths.
FPM DRAM is the Fast Page Mode DRAM. FPM DRAM sends the memory cell address only once to the processor for accessing the memory location for more than one time.
Extended Data Out DRAM (EDO DRAM)
Extended Data-Out (EDO) DRAM is a type of asynchronous DRAM. It is also known as Hyper Page Mode DRAM. It is faster than normal DRAM. This is because EDO DRAM starts fetching the data from the next cell before the previous process completes. Its approximate data transfer rate is 264 megabytes per second. It is about five to six percent faster than FPM DRAM.
Synchronous Dynamic Random Access Memory (SDRAM)
SDRAM synchronizes the memory speed with the CPU clock speed. The speed of the SDRAM depends on the speed of the CPU bus. It is faster than SRAM, DRAM, EDO DRAM, and VRAM memories. The data transfer speed of SDRAM is measured in nanoseconds and megahertz units. It runs with an average speed of 133 MHz.
There are two modules of SDRAMs:
2-clock SDRAM - In a 2-clock SDRAM, each clock signal controls two different DRAM chips.
4-clock SDRAM - In a 4-clock SDRAM, each clock signal controls four different DRAM chips. The recent computers use 4-clock SDRAM.
Rambus Dynamic Random Access Memory (RDRAM)
RDRAM is the fastest computer memory. It sends data very frequently on the data bus and read data on every rise and fall of the clock cycle. As a result, the RDRAM memory gets the data transfer speed of 800 MHz. The video memory on the graphic accelerator cards and the cache memories use this chip. The high-performance workstations and the servers use the RDRAM chip. The high bandwidth and the low latency applications also use this memory chip.
The RIMM module carries the RDRAM chip. RIMM means Rambus Inline Memory Module. The number of RDRAM placed on the module depends on the bus width of the RAM. RDRAM HAM Bus DRAM) of 160 or 184 Pins operates at 300-400 MHz.
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