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What are the speeds of SDRAM and DDRRAM?

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2015-09-12 07:52:03
2015-09-12 07:52:03

Check it out.... SDRAM comes only in 64 bit modules (long 168 pin DIMMs). SDRAM has a access time of only 6-12 ns. The performance improvement over EDO RAM was a mere 5 percent running at 66 MHz. At 100 and 133 MHz it proves better. DDR RAM is clock doubled version of SDRAM, which is replacing SDRAM during 2001-2002. RAMBUS (RDRAM) is a more futuristic RAM type. Intel and others had great expectations from this type, but it flopped in 2000-2001. MORE ON RAM KarbosGuide.com. Module 2e1. About RAM What is RAM? [top] This page should be read together with modules 2a, 2b, 2c, and 2d, which deal with system board, system bus, I/O bus and chip sets. When we talk about motherboard and chip sets, we cannot ignore RAM. Warning: RAM and RAM chips is a very complicated, technical subject area. I can in no way give a complete, comprehensive description of this subject. RAM is our working memory storage. All the data, which the PC uses and works with during operation, are stored here. Data are stored on drives, typically the hard drive. However, for the CPU to work with those data, they must be read into the working memory storage, which is made up of RAM chips. To examine RAM, we need to look at the following: RAM types (FPM, EDO, ECC, and SD RAM) RAM modules (SIMM and DIMM) in different versions RAM and the system bus First, let us look back in time. Not too many years ago, Bill Gates said, that with 1 MB RAM, we had a memory capacity, which would never be fully utilized. That turned out to be untrue. -------------------------------------------------------------------------------- Historical review Back in the 80s, PCs were equipped with RAM in quantities of 64 KB, 256 KB, 512 KB and finally 1 MB. Think of a home computer like Commodore 64. It had 64 KB RAM, and it worked fine. Around 1990, advanced operating systems, like Windows , appeared on the market, That started the RAM race. The PC needed more and more RAM. That worked fine with the 386 processor, which could address larger amount of RAM. The first Windows operated PCs could address 2 MB RAM, but 4 MB soon became the standard. The race has continued through the 90s, as RAM prices have dropped dramatically. Today. it would be foolish to consider less than 32 MB RAM in a PC. Many have much more. 128 MB is in no way too much for a "power user" with Windows 95/98, it is important with plenty of RAM. Click here to read about the swap file and RAM considerations. Windows 98 is a little better at handling memory, but still a lot af RAM is a good thing. The traditional RAM type is DRAM (dynamic RAM). The other type is SRAM (static RAM). SRAM continues to remember its content, while DRAM must be refreshed every few milli seconds. DRAM consists of micro capacitors, while SRAM consists of off/on switches. Therefore, SRAM can respond much faster than DRAM. SRAM can be made with a rise time as short as 4 ns. It is used in different versions in L2 cache RAM (for example pipe line BURST Cache SRAM). DRAM is by far the cheapest to build. Newer and faster DRAM types are developed continuously. Currently, there are at least four types: FPM (Fast Page Mode) ECC (Error Correcting Code) EDO (Extended Data Output) SDRAM (Synchronous Dynamic RAM) -------------------------------------------------------------------------------- A brief explanation of DRAM types FPM was the traditional RAM for PCs, before the EDO was introduced. It is mounted in SIMM modules of 2, 4, 8, 16, or 32 MB. Typically, it is found in 60 ns or 70 ns versions. 60 ns is the fastest and the one to use. You cannot mix different speeds on the same Pentium motherboard. EDO (Extended Data Out) RAM is an improvement of FPM RAM. Data are read faster. EDO extends the time that output data is valid, which betters timing issues between the CPU and RAM and this way improves the performance. By switching from FPM to EDO, one could expect a performance improvement of 2 to 5 percent. EDO RAM was usually sold in 60 ns versions. A 50 ns version was available at higher cost. EDO has now been replaced by the even faster SDRAM. ECC RAM is a special error correcting RAM type. It is especially used in servers. SDRAM (synchronous DRAM)): The replacement for DRAM, FPM, and EDO RAM types. SDRAM "locks" (synchronizes) the memory access to the CPU clock. This way we get faster data transfer. While one portion of data is tranported to the CPU another can be being prepared for transfer. SDRAM comes only in 64 bit modules (long 168 pin DIMMs). SDRAM has a access time of only 6-12 ns. The performance improvement over EDO RAM was a mere 5 percent running at 66 MHz. At 100 and 133 MHz it proves better. DDR RAM is clock doubled version of SDRAM, which is replacing SDRAM during 2001-2002. RAMBUS (RDRAM) is a more futuristic RAM type. Intel and others had great expectations from this type, but it flopped in 2000-2001. -------------------------------------------------------------------------------- 8 or 9 bits per byte? Normally you figure 8 bits to one byte. For many years, a ninth bit has been added as parity bit in the RAM blocks to verify correct transmission. That way you have to transmit 9 bits, to store 8 bits in the old 30 pin RAM chips. And it takes 36 bits to store 32 bits in the larger 72 pin chips, which increases the cost of the RAM chip by about 12%. If your motherboard requires 36 bit modules, you must respect that. Fortunately, most system boards accepts 32 bit modules, so this creates no problems. -------------------------------------------------------------------------------- RAM and motherboard [top] You cannot freely install your desired RAM type. RAM is controlled by the chip set on the motherboard, so you must install a type, which matches your motherboard. Furthermore, RAM chips come in different sizes, which must match the system board. On modern system boards, RAM is installed on SIMM or DIMM modules. Before, small individual DRAMs were used. There was usually room for 36 small chips on the system board. That made it cumbersome to install new RAM. Then, someone figured out to install RAM chips on cards, which are easily installed. First came the SIPP modules. They had multiple pins, which fit in the motherboard. Since then came the SIMM modules. They are mounted on a card, which has an edge connector. They fit in sockets on the motherboard, and anyone can install them. -------------------------------------------------------------------------------- RAM speeds [top] RAM speed is measured in ns (nano seconds). The fewer ns, the faster is the RAM. Years ago, RAM came in 120, 100 and 80 ns. Today, we are talking about 60 ns and faster. It becomes complicated to describe the relationship between RAM speed and the ability of the system bus to utilize fast RAM. I will gloss over that. But here is a table which illustrates RAM speed, relative to clock speed: Clock speed Time per clock tick 20 MHz 50 ns 25 MHz 40 ns 33 MHz 30 ns 50 MHz 20 ns 66 MHz 15 ns 100 MHz 10 ns 133 MHz 6 ns -------------------------------------------------------------------------------- Peak Bandwidth [top] Here you see the maximal peak bandwidth of the three well known RAM types. The figures illustrates the absolutely maximal transfer from RAM to the L2-cache - in peaks, not as continuously transferred. RAM type Max. peak bandwidth FPM 176 MB/sec EDO 264 MB/sec SD 528 MB/sec

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Speeds; MHz were raised drastically

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Occasionally on older motherboards, there are slots for SDRAM and DDR RAM but, they CANNOT be used at the same time, due to the different speeds they run at.

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No. SDRAM and DDR SDRAM are not compatible with each other.

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supplied by webopedia.com Short for Synchronous DRAM, a type of DRAM that can run at much higher clock speeds than conventional memory. SDRAM actually synchronizes itself with the CPU's bus and is capable of running at 133 MHz, about three times faster than conventional FPM RAM, and about twice as fast EDO DRAM and BEDO DRAM. SDRAM is replacing EDO DRAM in many newer computers. SDRAM is a variant of DRAM in which the memory speed is synchronized with the clock pulse from the CPU. This synchronization enables the SDRAM to pipeline read and write requests. Pipelining enables the SDRAM to accept commands at the same time as it is processing other commands. There are three variants of SDRAM: Single Data Rate SDRAM - SDR SDRAM Dual Data Rate SDRAM - DDR SDRAM

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DDR SDRAM The Double Data Rate SDRAM is a RAM standard created by JEDEC. DDR SDRAM is the most common video RAM teshnology found on recent video cards. DDR SDRAM is designed to transfer data at speeds twice that of conventional SDRAM by transferring data on both the rising and falling parts of the processing clock cycle.

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Ddr3 sdramsolid state technology has the fastest read/write speeds of current hard drives.

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PC133 is an SDRAM standard. SDRAM is a type of RAM.

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Physical size of the memory card. Mobile sdram is smaller than sdram for desktops.

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No. SDR SDRAM and DDR SDRAM modules are not interchangeable.

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2 on desktop non DDR SDRAM and 1 on laptop SDRAM

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Sdram has one notch. Depending upon the model of Sdram the number of pins it has can vary but a standard Sdram has 184 pins.

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The fastest technology in actual is laan, laan is the longest and most profound memory ever.

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DDR SDRAM uses 184 pins.

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The term DDR SDRAM refers to the phrase "double data rate synchronous dynamic random access memory". DDR SDRAM is simply a faster version of SDRAM in which data travels at a double rate. If your computer specs say that it uses DDR SDRAM it can take DDR SDRAM, but not SDRAM. DDR is 184 pins and has a notch in the bottom near the center and you will be unable to put DDR in an SDRAM mother board and also unable to put SDRAM in a DDR motherboard. Recently a new type of RAM has been introduced to market called DDR2. DDR2 is its own type and will not fit into a DDR motherboard. Hope this helps. Peace.

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SDRAM modules are available in sizes ranging from 16 MB to 1 GB.

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Dram and Sdram are two different types of memory.

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Most desktops and notebooks use one of the three most popular types of synchronous dynamic random access memory (SDRAM) for the main system memory. Single data rate (SDR) SDRAM is the older type of memory, commonly used in computers prior to 2002. Double data rate (DDR) SDRAM hit the mainstream computer market around 2002, and DDR2-based systems hit the market in mid-2004. DDR SDRAM is a straightforward evolution from SDR SDRAM. The big difference between DDR SDRAM and SDR SDRAM is that DDR reads data on both the rising and falling edges of the clock signal, so the DDR module can transfer data twice as fast as SDR SDRAM. While DDR has a limited clock rate, the evolutionary changes to DDR architecture enable DDR2 to achieve speeds beyond of DDR, delivering bandwidth of 5.3 GB per second and beyond! Because DDR2 is able to operate with faster bus speeds, your memory doesn't hold back the performance of your processor. Generally speaking, motherboards are built to support only one type of memory. You cannot mix and match SDRAM, DDR, or DDR2 memory on the same motherboard in any system. They will not function and will not even fit in the same.

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In order to upgrade SDRAM with DDR, you will need to replace your motherboard. DDR uses a different slot than SDRAM, so if your motherboard is using SDRAM currently, you will most likely have to replace your motherboard in order to make your system support DDR.

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The actual term for computer memory SDRAM is Synchronous Dynamic Random Access Memory. You can learn more about SDRAM online at the Wikipedia website.

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SDRAM is faster and better performance than EDO

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DDR SDRAM has one notch and uses 184 pins.

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DDR SDRAM performs 2 transfers per clock cycle

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Ddr dimm has 184 Sdram dimm has 168


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