Memory: Memory frequency

The memory clock speed is the same as the CPU clock speed. It is used to indicate the memory speed. It represents the maximum operating frequency that the memory can achieve. The memory clock speed is measured in MHz (MHz. The higher the memory frequency, the faster the memory can reach. The memory clock speed determines the maximum operating frequency of the memory. At present, the mainstream memory frequency rooms are 333mhz and 400mhz DDR memory, as well as 533mhz and 667mhz DDR2 memory.

We all know that the clock speed of computer systems is measured by frequency. The crystal oscillator controls the clock speed. When voltage is added to the silicon wafer, it vibrates in the form of a sine wave. This vibration can be recorded through the deformation and note of the wafer. The vibration of the crystal is presented in the form of sine harmonic current, which is the clock signal. The memory itself does not have a crystal oscillator, so the clock signal during memory operation is provided by the North Bridge of the Motherboard chipset or directly by the clock generator of the motherboard, that is, the memory cannot determine its operating frequency, the actual working frequency is determined by the motherboard.

The frequency of the DDR memory and DDR2 memory can be expressed by the operating frequency and equivalent frequency. The operating frequency is the actual operating frequency of the memory particles, however, because the DDR memory can transmit data at both the pulse rise and the descent edge, the equivalent frequency of data transmission is twice the working frequency; in DDR2 memory, each clock can read/write data at four times the operating frequency. Therefore, the equivalent frequency of data transmission is four times the operating frequency. For example, the operating frequency of DDR 200/266/333/400 is 100/133/166/200 MHz, while the equivalent frequency is 200/266/333/400 MHz. The operating frequency of DDR2 400/533/667/800 is 100/133/166/200 MHz, respectively, the equivalent frequency is 400/533/667/800 MHz.

The asynchronous memory working mode has multiple meanings. in a broad sense, any memory working frequency that is inconsistent with the external CPU frequency can be called the asynchronous memory working mode. First, the earliest asynchronous memory working mode appeared in the early Motherboard chipset, the memory can work in a mode that is 33 MHz or 33 MHz higher than the external frequency of the CPU (note that the difference is only 33 MHz), so that the system memory performance can be improved or the old memory can continue to use the residual heat. Secondly, in normal working mode (CPU is not overclock), many Motherboard chipset also support asynchronous memory working mode, such as Intel 910gl chipset, only 533 MHz FSB (MHz) CPU external frequency is supported, however, it can work properly with a 133mhz DDR 266 working frequency, a 166mhz DDR 333 working frequency, and a 400 MHz DDR 400 working frequency. the operating frequency is MHz ), however, the performance of different memory combinations varies. Again, in the case of CPU overclocking, in order not to make the memory slow down the CPU overclocking capability, you can lower the memory operating frequency to facilitate overclocking, for example, the opteron 939 of AMD's socket 144 interface is very easy to overclock, and the external frequency of many products can easily exceed 300 MHz. If this is in the memory synchronization mode, at this time, the equivalent memory frequency will reach DDR 600, which is obviously impossible. In order to smoothly exceed the MHz external frequency, we can set the memory in the BIOS of the motherboard to DDR 333 or DDR 266 before the overclock. After the overclock is over 500 MHz, the former is only DDR (some of the best memory can be reached ), while the latter only has DDR 400 (completely normal standard frequency). Therefore, setting the asynchronous memory mode correctly helps overclock success.

The current Motherboard chipset supports almost all of the memory Asynchronization. Intel supports all of the new 810 series from the 875 series to the present, while Weisheng provides all of the functions since the 693 chipset.