What does 667,800 etc mean after the memory transfer standard?

At the same operating frequency of 100MHz, the actual frequency of DDR is 200MHz, while DDR2 can reach 400MHz.

Other words. The number after DDR2 refers to his actual frequency.

So why is the actual frequency of DDR twice the operating frequency and DDR2 4 times?

DDR=Double Data Rate.

Strictly speaking, DDR should be called DDR SDRAM, people are used to calling it DDR, and some beginners often see DDR SDRAM, and think that SDRAM is the abbreviation of Double Data Rate SDRAM, which means Double Rate Synchronous Dynamic Random Access Memory.

The DDR2DDR2 DDR II (Double Data Rate 2) SDRAM is a new generation of memory technology standard developed by JEDEC (Joint Committee on Electronic Equipment Engineering), and the biggest difference between it and the previous generation DDR memory technology standard is that although it adopts the basic method of data transmission at the same time as the clock rises and falls, DDR2 memory has twice the pre-read capability of the previous generation DDR memory (i.e., 4-bit data read pre-fetching). In other words, DDR2 memory is capable of reading and writing data at 4 times the speed of the external bus per clock, and can run at 4 times the speed of the internal control bus.

So you get the idea.

However, although DDR2 is the successor generation of DDR, there is still a problem that will be more prominent in some areas compared to DDR.

Latency: In DDR and DDR2 memory with the same operating frequency, the memory latency of the latter is slower than that of the former. For example, DDR 200 and DDR2-400 have the same latency, while the latter has twice the bandwidth.

Actually, DDR2-400 and DDR 400 have the same bandwidth, they are both, but the core operating frequency of DDR400 is 200MHz, while the core operating frequency of DDR2-400 is 100MHz, which means that the latency of DDR2-400 is higher than that of DDR400.

Frequency. The maximum frequency of work is.

The unit is mhz, the higher the faster. There are also 1033MHz

It means that the memory frequency is 667MHz and 800mmhz, which can be used stably in a unified working environment. But there are a few things that must be understood:

1.The capacity of memory is much larger than the bandwidth, so the actual difference between the two is very small for the same capacity. (As long as the capacity is enough to play the game, the frequency and timing are puffy clouds.) ）

and 800, the frequency is different, the bandwidth is different. There is a certain gap in theory. The higher the frequency, the faster the memory, and the better the memory.

3.Some special applications require large memory bandwidth, such as large-scale 3D games, animation rendering, PS, AE, etc., which require large memory bandwidth to reflect the difference between the two, but the difference is far less than the proportion of numbers.

4.In the actual operation and use of the computer, the difference in the frequency of different memories is almost imperceptible. That is to say, it is equivalent to use.

For example, the difference in memory frequency is not noticeable in 3ds Max when modeling, and the acceleration effect on rendering is not obvious. The factors that affect the rendering speed are the CPU speed and the memory size.

In most DX9 3D games, the difference is also relatively small).

5.Most of the 667 memory with good physique can exceed 800.

This means that DDR2 667MHz memory can be used with DDR2 800MHz memory. However, using them together will reduce the frequency. It is recommended to use 2G DDR2 800 memory, and if possible, use two to form 4G, and then use a 64-bit system.

It's a strip that can be used at either 667 or 800.