What is DDR? What does PC-6400 mean

[Vivan]

Hi everybody,

In recent years, CPU speed has increased exponentially. However, the growth rate of computer memory really unsatisfactory. This year, a new type of memory PC-6400 : DDR memory has already been published. For most people, DDR is still an unfamiliar term, however, it is indeed hundreds of top-3 memory and system designers to work together in the crystal. The emergence of DDR memory bandwidth and performance indicates the overall increase, however, compared with Rambus memory is more important is that DDR is cheaper. Any idea?

[Raine]

DDR is Double Data Rate. DDR synchronous dynamic random memory with the ordinary (DRAM) is very similar. General synchronous DRAM (now called SDR) standard DRAM different. Standard DRAM receives the address of the command word formed by the two addresses. To save input pin, using the multiplexing method. The first address word from the line address strobe (RAS) locks exist DRAM chips. RAS command immediately after the column address strobe (CAS) latching the second address word. Through the RAS and CAS, the stored data can be read.

[Sam.D]

PC-6400 standard is that DDR2-800 memory, PC6400 DDR memory, such as representing the speed, pc6400 shows speed 6400MB/S. SDR DDR RAM memory and works basically the same, but the DDR clock pulse in both rising and falling edge of read data, so the data transfer rate can be twice the clock frequency. A new generation of DDR memory operating frequency and data rate of 200MHz, respectively, and 266MHz, and this corresponds to the clock frequency of 100MHz and 133MHz.

[ZeDaX]

DDR chip test chip in the early stages of both the final packaging stage also. Tester is usually used in automatic test equipment memory, the value of several millions of dollars in more than ordinary. The core part of the tester is a programmable high-resolution signal generator. Test engineers programmed to simulate the actual working environment; In addition, he also can fine-tune the timing pulse edge around to find the balance.

[ThoMas321]

DDR memory, the memory market is now gradually becoming the new darling of the reasonable cost from its inception has been overwhelming expectations of the people, hoped that the new memory products overall system processing speed and bandwidth, and even have on Rambus infinite hope Intel Corporation announced to the outside world will be the fastest production support DDR memory, a new generation of P4 system. Not difficult to see, DDR really is the trend.

[Alondra]

The work in the similar frequency of 100MHz, DDR actual frequency is 200MHz, and DDR2 can reach 400MHz. So too there is another problem: in the same frequency of the DDR and DDR2 memory, which memory latency slower than the former. For example, DDR 200 and DDR2-400 have the same delay, which has twice the bandwidth. In fact, DDR2-400 and DDR 400 with the same bandwidth, they are 3.2 GB/s, DDR400, but the core of the operating frequency is 200MHz, and DDR2-400's core speed is 100MHz, the delay means that DDR2-400 higher than DDR400.

[pcs365_12]

DDR is dual sided dynamic RAM with very high bus speed for the new motherboards supporting high fsb