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Types of RAM
This document discusses different types of RAM. It begins by introducing RAM as random access memory that can be accessed in any order and location. The two main types are static RAM (SRAM) and dynamic RAM (DRAM). SRAM is more expensive but has very low access times, while DRAM is lower cost but needs periodic refreshing. The document then describes different variants of DRAM over time that provide faster access, including FPM, EDO, SDRAM, DDR, DDR2 and RDRAM.
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Types of RAM
- 2. Outline • Introduction . •RAM types . • DRAM . • SRAM .
- 3. Introduction RAM “Random AccessMemory” is a form of data storage that can be accessed randomly at any time, in any order and from any physical location., allowing quick access. RAM is volatile i.e. its contents are lost when the device is powered off. RAM allows the computer to read data quickly to run applications. It allows reading and writing.
- 4. RAM types The twomain types of RAM are static RAM and dynamic RAM. Static RAM (SRAM) 4 times more expensive Very low access time . Information stored on RS flip-flops . No need for refreshing . They made of transistors it is used in cache . They can be either Bipolar or MOS technology . Dynamic RAM (DRAM) Low cost . Consumes less power . Information stored on FET transistors . Needs to be refreshed . These are mostly made of capacitors . it is used in main memory These are available only in MOS technology
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- 6. FPM RAM • FastPage Mode Dynamic Random Access Memory It was the original form of DRAM. It waits through the entire process of locating a bit of data by column and row and then reading the bit before it starts on the next bit. Maximum transfer rate to L2 cache is approximately 176 Mbps.
- 7. EDO RAM • Extendeddata-out Dynamic Random Access Memory does not wait for all of the processing of the first bit before continuing to the next one. As soon as the address of the first bit is located, EDO DRAM begins looking for the next bit. It is about five percent faster than FPM. Maximum transfer rate to L2 cache is approximately 264 Mbps.
- 8. SDRAM • Synchronous DRAM. • SDRAM is a type of dynamic random access memory which is synchronized with the clock speed that the microprocessor is optimized for. SDRAM is about five percent faster than EDO RAM and is the most common form in desktops today. Maximum transfer rate to L2 cache is approximately 528 Mbps.
- 9. DDR RAM • Doubledata rate synchronous dynamic RAM is just like SDRAM except that is has higher bandwidth, meaning greater speed. It is a newer variant of SDRAM. Maximum transfer rate to L2 cache is approximately 1,064 Mbps .
- 10. DDR2 RAM • DoubleData Rate 2 . • newer version of DDR . • twice as fast as the original DDR RAM. • 2003 . • still is double data rate just like the original DDR. • DDR2-RAM has modified signaling which enables higher speeds to be achieved with more immunity to signal noise and cross-talk between signals .
- 13. RDRAM • Rambus dynamicrandom access memory : Designed by Rambus, RDRAM uses a Rambus in-line memory module (RIMM), which is similar in size and pin configuration to a standard DIMM. RDRAM memory chips work in parallel to achieve a data rate of 800 MHz, or 1,600 Mbps. Since they operate at such high speeds, they generate much more heat than other types of chips .
- 17. REFERANCE • http://www.diffen.com/difference/RAM_vs_ROM • http://en.wikipedia.org/wiki/Random_access_memory •https://www.google.ps/search?tbm=isch&q=compare+bet ween+type+of+DRAM+&ei=Lxk0VaDUB4HasgH0qISoBg#imgrc =_ • MEMORY : RAM AND ITS USES – SHARDA UNIVERSITY - School of Engineering & technology - DIGITAL ELECTRONICS – I • Computer Organization and Architecture Designing for Performance (8th Edition)
Editor's Notes
- #7 Dynamic RAM (DRAM) The term "Fast Page Mode" comes from the capability of memory being able to access data that is on the same page. 486 and Pentium .
- #8 Extended Data Out DRAM Once the required data is found the searching for the next bit will start Output is about 264 Mbps . refers to fact that the data output drivers on the memory module are not switched off when the memory controller removes the column address to begin the next cycle .
- #9 Synchronous DRAM Once the first bit is found reads the data from the entire row. Relies on the fact that data is written in rows Output is about 528 Mbps SDRAM is capable of running at 133MHz which is about three times faster than FPM RAM and twice as fast as EDO RAM .
- #10 Double Data Rate SDRAM Reads data from memory on the rising clock and falling clock signal. Allowing double capacity over SDRAM Output is about 1064 Mbps transfers data twice per clock cycle which effectively doubles the data rate . become mainstream in the graphics card market and has become the memory standard.