Questions about DRAM frequency variation 10

This is because the frequency of your memory is synchronized with the external frequency of the CPU. Even when the CPU external frequency prompts, the memory frequency also increases. You just turn off this synchronization relationship between the CPU and the memory in the CMOS.

This function is generally put together with adjusting the CPU frequency, you can look for it in the CPU and memory overclocking projects.

Synchronization here refers to the fact that the CPU frequency increases in proportion to the memory frequency, not that the CPU and memory frequency are the same.

The memory speed is determined by the memory hardware itself, which is burned and cannot be changed through software control... Both the CPU and the graphics card can be controlled.

There is no 800, only 737, which means that the maximum DRAM frequency supported by your motherboard is so large (different motherboards are different), fortunately, now the motherboard has automatic adjustment, if it is exceeded, it will be automatically reduced.

You don't have to adjust anything ... Besides, I've been doing this for many years, and I've never tried to change the frequency myself, so honestly, it doesn't make much sense.

AMD's platform, the CPU on which you have a different default crossover is also different, so it doesn't have to be running at 800

There is an option in the BIOS that you can adjust by yourself, or you can slightly exceed the external frequency of the CPU, so the memory frequency will follow.

DRAM is what we often call memory.

Most of the memory today is DDR class (mainly DDR2 and DDR3). To put it simply, the meaning of DDR is Double Data Rate, and there is this double, so you need to multiply 400MHz by 2.

The common description of how to achieve double the rate is that DDR memory transmits data twice in a clock cycle, and it can transmit data once in each of the rising and falling phases of the clock, so it is called double rate synchronous dynamic random access memory.

As for the frequency 400 of the specific detection of CPU-Z, it can be regarded as the actual "working frequency" (how the working frequency works, this needs to be answered thoroughly by professionals). And 800, we can think of it as the "effective frequency" at which the memory works in double operation.

The landlord An An.

The frequency detected by the CPU-Z is the physical frequency, and the DDR memory we are using has doubled the effective clock frequency because the data is transmitted once along the rising and falling edges of the clock, which means that a physical clock of 266MHz is actually equivalent to 533MHz.

The landlord's 245MHz is actually 490MHz. This frequency is not the standard frequency of JEDEC.

There are two cases:

One is that the landlord uses AMD processors with C&Q technology, and the c@q is turned on, because AMD processors have built-in memory controllers, and the memory frequency changes with the processor frequency as C&Q is turned on.

The other is that the landlord has set the wrong memory allocation ratio within the BIOS.

It's DDR533, it's a bit low but it's also in the normal range. Under the BIOS setting, the ratio of external frequency to memory is increased, and (of course, the motherboard supports the premise) to increase the external frequency, but that involves overclocking. Finally, it's not z-cpu, it's cpu-z

This is because the frequency of your memory is synchronized with the external frequency of the CPU. Even when the CPU external frequency prompts, the memory frequency also increases. You just turn off this synchronization relationship between the CPU and the memory in the CMOS.

This function is generally put together with adjusting the CPU frequency, you can look for it in the CPU and memory overclocking projects.

Synchronization here refers to the fact that the CPU frequency increases in proportion to the memory frequency, not that the CPU and memory frequency are the same.

Questions from anonymous users.

The skydram frequency is the real clock frequency in some software.

DDR2 uses a 4-pass transmission mechanism!

The actual frequency of DDR2 667 is indeed only 166! The equivalent frequency is 166*4=667

The reason why the real clock frequency of DDR2 667 is 333! That's right!

In fact, there is a link that everyone has not paid attention to! That's the "4-time transfer mechanism"!

DDR2's 4-pass transmission mechanism is not done in a single cycle!

It prescribes 2 transmissions for one cycle! From a physical point of view, the frequency is based on a period, that is to say, DDR2 667 is physically running at a frequency of 166*2=333! That's why 333 is displayed on the software!

But in the end, the equivalent frequency is still 667! Because it takes 2 cycles to do the job "once"!

133MHz, which is often referred to as DDR266, this cavity imitation also depends on what model your CPU is, and what is the frequency of the front-side bus it supports! If his front-side bus is 100MHz, then only 133MHz will be displayed here, and if DDR2400 is displayed, then under normal circumstances, the front-side bus should be 200MHz