what does DDR means in computer ?

Answer 1

Simple DDR Explanation
DDR works by taking a driven clock - front side bus frequency usually and modified by multipliers/divisors, enabling it to run to its rated frequency - and outputting two bits of data onto the memory bus from the DRAM's I/O buffers, per driven clock cycle. This is done on the rising and falling edge of that driven clock with DDR, giving it the double data rate moniker; data is read from and written to the bus twice per clock cycle, compared to SDR memory.

The mechanisms that allow a collection of DRAMs on a DDR DIMM to do that, outputting two bits of data per driven clock cycle, aren't too difficult to understand, but can be easily skipped over if you don't want to know the details. Here's a quick summary.

The CPU requests data from a certain memory address and passes that address over the CPU-to-memory controller bus. The memory controller recieves the data request and opens the correct memory bank on the DRAM that holds it, on the correct installed DIMM in the computer. The DRAM is arranged as an array of memory cells, in regular rows and columns. Accesses to the DRAM are done on a column by column basis, so the correct column on the DRAM is accessed and the DRAM instructed to deposit the contents of the address required onto the output pins of the memory module, allowing the memory controller to access it and pass it back to the CPU. The same happens during a memory address write, however the memory controller puts the data on the input pins of the memory module and its written to the DRAM on the correct column, held open like before.

Obviously that's done on a clock cycle basis, from the driven clock of the memory controller, and the DRAM accesses are also governed on a cycle by cycle basis internally. This is where memory timings come in, for example tRAS, the minimum time a memory bank needs to be held open, in numbers of cycles, so that a successful read or write can happen without data corruption. Data buffers on the DRAMs are used to buffer input and output from the cells on the DRAMs to the I/O pins on the module. It's these data buffers that are the key to understanding the difference between DDR and DDR-II.

So per driven clock cycle on the memory controller, the DRAM device can work with two bits of data, twice per clock (DDR), using the mechanism outlined above. Here's how DDR-II takes a different approach with its data buffers, to offer double the data frequency (effective bandwidth) for the same driven clock.

Answer 2

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Double Data Rate, the successor to the original SDRAM and the successor to DDR is DDR2. Buy a new computer today and it will most likely come with DDR3. All are each proprietary to themselves. There are some main boards that do more but that are not widely used so you can not swap between types. You have to use what the board is made for and if you add to what is there it has to be the same even if the board does both. If you want to use or copy info from a hard drive that was in an older computer to a new computer, the RAM speed is of little consequence. The only problem you may have is if the new computer can connect a PATA drive id the drive is that old and if not you can buy adapters pretty cheap to connect it via USB

Answer 3

Ddr Computer

Answer 4

What is DDR?
Stands for "Double Data Rate." It is an advanced version of SDRAM, a type of computer memory. DDR-SDRAM, sometimes called "SDRAM II," can transfer data twice as fast as regular SDRAM chips. This is because DDR memory can send and receive signals twice per clock cycle. The efficient operation of DDR-SDRAM makes the memory great for notebook computers since it uses up less power.

Answer 5

DDR SDRAM or double-data-rate synchronous dynamic random access memory is a class of memory integrated circuit used in computers. It achieves greater bandwidth than the preceding single-data-rate SDRAM by transferring data on the rising and falling edges of the clock signal (double pumped). Effectively, it nearly doubles the transfer rate without increasing the frequency of the front side bus.

Thus, a system with a 100 MHz front side bus has an effective clock rate of 200 MHz when DDR SDRAM memory is installed. The same system using SDR (single data rate) SDRAM, will not have its front side bus rate doubled and be limited to a 100 MHz front side bus speed.

With data being transferred 64 bits at a time, DDR SDRAM gives a transfer rate of [mbcr x 2 x 64] / 8; annotated it looks like this: (memory bus clock rate) × 2 (for dual rate) × 64 (number of bits transferred) / 8 (number of bits/byte). Thus with a bus frequency of 100 MHz, DDR-SDRAM gives a max transfer rate of 1600 MB/s.

JEDEC has set standards for speeds of DDR SDRAM, divided into two parts: The first specification is for memory chips and the second is for memory modules.

As DDR is superseded by the newer DDR2, the older version is often now referred to as DDR1.

Answer 6

Double data rate is a type of SDRAM in which data is sent on both the rising and falling edges of clock cycles in a data burst. It is usually referred to as DDR as opposed to DDR SDRAM.

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Answer 7

DDR/DDr2 is the bandwidth speed of your Random Access Memory chips (RAM) Theres currently DDR3 out for most RAM made today. If you want a faster load up, multitask better, and other quaint improvements you go with DDr2 or DDR3 memory. as for the hard drive, the speed transfer of that is determined by the RPM at which it is spinning and the SATA connection. SATA 6 GB/s means that up to6 gigs of information can be transfered in one second. DDR/DDR2/DDr3 doesnt affect your hard drive at all.

Answer 8

its just a type of memory chip, whats known as ram

its actual meaning is

DDR SDRAM or double-data-rate synchronous dynamic random access memory

your computer needs it to run the operating system

Answer 9

What Is Ddr

Answer 10

Double data rate (DDR)
synchronous dynamic random access memory (SDRAM)