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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
What else can I help you with?
What advantage does DRAM have over SRAM?
Dynamic Random Access Memory contents need to be continuously refreshed. When its contents are being refreshed, memory can not be read from nor write to. Another point to note is that DRAM is cheap to manufacture (This could be the only advantage it has to SRAM).Where as in Static Random Access Memory, memory need not to be continuosly refreshed and therefore memory can be accessed at any time. SRAM is expensive to manufacture.
Why you do not need refreshing circuit in sram?
SRAM (Static Random-Access Memory) stores data using a bistable latching circuit, which eliminates the need for refreshing circuitry found in DRAM (Dynamic Random-Access Memory). The stored data in SRAM remains intact as long as power is supplied to the memory cells, making it faster and simpler to access compared to DRAM.
What is the difference between DRAM and SRAM in terms of pin diagram?
dram is material gives sound and sram is the sound itself
What functions of dram versus sram of a computer?
Static Random Access Memory (SRAM) entries are constant and fixed, the information stored in this type of memory does not degrade over time. Dynamic Random Access Memory (DRAM) slowly leaks over time and must be refreshed from time to time.
RAM is divided into what two categories?
There are two different types of RAM: DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory). DRAM is more common. It needs to be refreshed about 1,000 times per second. It also supports access times of about 60 nanoseconds. SRAM is more expensive. It does not need to refresh so it is faster than DRAM. It supports access times as low as 10 nanoseconds.
What are different types of rams?
sram and dram
RAM uses static memory or dynamic memory?
Well, it can be either. There is DRAM (Dynamic random access memory) and SRAM (Static random access memory). DRAM is a much more simple and inexpensive type of memory, it only requires one transistor and capacitor per bit where as SRAM requires four transistors. However, SRAM is faster and uses much less power.
What adventage does dram have over sram?
DRAM has a lower price. Further details below:
How would you write about SRAM?
---SRAM--- Static random access memory (SRAM) is a type of semiconductor memory where the word static indicates that it, unlike dynamic RAM (DRAM), does not need to be periodically refreshed, as SRAM uses bistable latching circuitry to store each bit. SRAM exhibits data remanence, but is still volatile in the conventional sense that data is eventually lost when the memory is not powered. The term SDRAM, which stands for synchronous DRAM, should not be confused with SRAM.
Ram is divided into two categories what are they?
DRAM and SRAM
Why sram less dense than dram?
SRAM is less dense than DRAM because SRAM cells are made up of multiple transistors, typically 6 transistors per cell, which require more space compared to the single transistor used in DRAM cells. This extra space needed for each cell in SRAM makes it less dense in terms of storing data compared to DRAM.
What is the need of cache in computer?
Definition from webopedia: portion of memory made of high-speed static RAM (SRAM) instead of the slower and cheaper dynamic RAM (DRAM) used for main memory. Memory caching is effective because most programs access the same data or instructions over and over. By keeping as much of this information as possible in SRAM, the computer avoids accessing the slower DRAM. So basically, to have a faster form of RAM for data to be stored in to so the CPU doesn't have to constantly write and re-write into DRAM. Also distance plays a factor in the speed to the access times. Cache is either on or in between the the slower DRAM. The shorter the distance the faster the access times.
