What is the difference between memory DDR and SD?

DDR memory is dual date rate sdram in English"Double-rate SDRAM", which can be reached at a front-side bus frequency of 133MHz. It works on the principle that it can transmit data on both the upper and lower edges of the trigger edge of the control clock (while the SDRAM only transmits data on the lower edge of the control clock), so the DDR SDRAM can exchange data twice during a control signal, which is much faster than the previous SD memory.

In DDR memory, because of the difference in clock frequency, there are three differences: DDR266, DDR333 and DDR400, generally speaking, the higher the clock frequency, the faster the memory speed, and its ** difference is not too great, so as long as the motherboard supports higher memory frequency, you should buy higher speed memory. In use, due to the higher and higher requirements for the memory of the software, the minimum capacity of the memory should be more than 256M, for the use of computers to play big games and database calculations and plane stereoscopic design users, it is more necessary to choose a computer with a memory capacity of 512M or even higher.

SDRAM is the abbreviation of "synchronous dynamic random access memory", which means "synchronous dynamic random access memory", which is what we usually call "synchronous memory", this kind of memory adopts a 168-line structure, and the schematic diagram of the memory and its slots is as follows:

Theoretically, SDRAM is synchronized with the CPU frequency, sharing a clock cycle. SDRAM consists of two interleaved storage arrays, and when the CPU accesses data from one storage array, the other is ready to read and write data, and the read efficiency is multiplied by the tight switching of the two storage arrays. Currently, the latest SDRAM has a storage speed of up to 5 nanoseconds.

ddr sdram

DDR is a memory technology produced after SDRAM, DDR, which originally means "doubledatarate" in English, as the name suggests, is a dual data transfer mode. The reason why it is called "double" means that there is "single", the SDRAM we use daily is "single data transmission mode", the characteristic of this memory is to perform an operation (read or write) on the rising edge of a square wave in a memory clock cycle, and DDR refers to a new design, which operates once on the rising edge of the square wave in a memory clock cycle, and also does an operation on the falling edge of the square wave. DDR can complete the task that can only be completed by two cycles of SDRAM, so theoretically, the performance of DDR memory at the same rate is more than double that of SDR memory, which can be simply understood as 100MHz DDR=200MHz SDR.

DDR memory adopts 184-line structure, DDR memory is not backwards compatible with SDRAM, requiring a motherboard and system designed for DDR

One is with PIIII master and one is PIIII.

One has two card slots, and the other has only one.

I don't know which one is which exactly.

Although DDR is faster than SDRAM, it is twice as fast as SDRAM, so the latency performance is worse than SDRAM, but in general DDR performance is better.

What does DDR and SDR memory mean on a desktop computer and how can you tell the difference? What are the advantages of each?

What does DDR and SDR memory mean on a desktop computer and how can you tell the difference? What are the advantages of each? Hello dear, the specific differences between SDRAM and DDR are as follows:

1. There is a difference in transmission rate: the traditional SDRAM can only transmit data on the rising edge of the signal, while DDR can only transmit data on the rising edge and falling edge of the signal, therefore, the data transmission amount of DDR memory in each clock cycle is twice that of SDRAM, which is also the meaning of DDR dual data rate and dual data rate. 2. There are differences in the appearance slots

DDRs differ from SDRAM in shape and size, they have similar size and pitch, and the standard DDR memory module is a 184-pin DIMM (double-sided DIMM). The DDR is very similar to the standard 168-pin SDRAM, with the biggest difference being that the DDR uses only one slot, while the SDRAM uses two. 3. There are differences in design

Compared to SDRAM, DDR employs more advanced synchronization circuitry, which makes the main steps of sending and outgoing specified addresses and data not only independent, but also fully synchronized with the CPU. DDR uses delay-locked cyclic ring technology, which the memory controller can use to filter the data to pinpoint the data when it is active, output it every 16 times, and resynchronize the data from the different memory modules. I hope I can help you!

If my answer is helpful to you, please give a thumbs up (comment in the lower left corner), look forward to your like, your efforts are very important to me, your support is also the motivation for my progress, and finally I wish you good health and a happy mood!

Memory can also be called main memory. It is a storage space that can be directly addressed by the CPU, and is made of semiconductor devices. Memory is characterized by a fast rate of accessing data.

Memory is the main component in a computer, and it is relative to external memory. The programs we usually use, such as Windows operating system, typing software, game software, etc., are generally installed on external memory such as hard disks, but only this can not use its functions, they must be transferred to the memory to run, in order to really use its functions, we usually enter a piece of text, or play a game, in fact, are carried out in memory. It's like in a study room, the shelves and bookcases where books are stored are equivalent to the external memory of the computer, and the desk we work on is the memory.

Usually we store a large amount of data to be saved permanently in external memory, and put some temporary or small amounts of data and programs in memory, of course, the quality of memory will directly affect the running speed of the computer.

Compared with SDRAM: DDR uses more advanced synchronization circuitry, so that the main steps of specifying address, data transmission and output can be performed independently, and the CPU is fully synchronized. DDR uses DLL (Delay Locked Loop) technology, which is used by the memory controller to pinpoint the data when it is active, output it every 16 times, and resynchronize the data from the different memory modules. DDR essentially does not require an increase in clock frequency to double the speed of SDRAM, and it allows data to be read out on the rising and falling edges of the clock pulse, thus being twice as fast as standard SDRAM.

In terms of form factor, DDR is not much different from SDRAM, they have the same size and the same pin distance. However, the DDR is 184 pins, 16 more than SDRAM, and mainly contains new control, clock, power, and ground signals. DDR memory uses the SSTL2 standard, which supports voltage, rather than the LVTTL standard for voltages used by SDRAM.