Today we will consider the latency of RAM. What is this and why is this characteristic needed in computer technology? Where did it find its use? How to achieve the best value of this characteristic?
About RAM
This is the name of a special device in which the data is located and the processes running during the operation of the computer are executed. Because of its speed, it acts as an intermediary between the information located on the hard drive and the processor. The most understandable for most people is the amount of RAM. In this case, the rule is that the more it is, the better for us. In fact, now for using the Internet, watching movies and working with most useful programs, 2 GB is enough. But for performance evaluation, a number of other parameters are used, for example frequency. It indicates how much data can be sent on the bus in one unit of time. The higher the frequency, the higher the information transfer rate. But you need to consider that it is also supported by the processor and the motherboard. Or let's take another parameter, not so well-known - latency. This is the name for the time delays of signals that come from the RAM. The lower the performance of the computer, the better the result in terms of efficiency will eventually come about.
Latency Features
In the previous paragraph, one significant moment was missed. Along with the value of the RAM frequency, the latency of the RAM also increases. What is better then OP? How to choose more or less universal indicators? It is considered optimal to use several memory models. So, if there are two of them, and they work in two-channel mode, then the data transfer rate will be increased. To do this, the boards used must be installed in certain slots (which, as a rule, are highlighted in one color). There is such a feature: it is not necessary that they have the same amount of memory. But with respect to frequency, it is desirable here to get a complete coincidence. Otherwise they will work with the smallest of the two.
What is the latency of memory?
A little more theory. This is what summation is called, which is carried out using a special coefficient of uncontrolled reverse transistor currents that are included in each chip of the memory line used, as well as the time of their switching. This may seem complicated, but this is a misleading assumption. So, latency depends on the frequency with which the chips work. Interestingly, it is not proportional. In other words: the less latency, the better for the user. Let's look at an example. We want our operational memory to be two gigabytes in size in our hypothetical computer . We can put one line that will give us 2 GB. But this is not the most optimal way. In this case, it is best to install four rulers, each with 512 MB. In this case, you should also take into account the influence of the motherboard, as well as the types of RAM used. A module made on the basis of one technology can not be put in place, which is intended for another technology. This is implemented in order to exclude damages during operation of the mechanism not intended for these conditions.
Designation
If you ever viewed a device, you could see something similar to the following: "Latency of RAM: CL9". What does it mean? This indicator indicates a specific delay that occurs between the start of sending the column address to the memory and, accordingly, the actual data transmission. The figure indicated is the amount necessary to start the process. The smaller it is, the better for us. Therefore, when choosing RAM, it is always necessary to take into account this value.
Types of devices
To split by features, double data rate (DDR) is used, which can be translated as a double data rate. The first samples of this technology had 184 contacts. Their standard supply voltage was 2.5 V. It makes a sample of 2 bits of data per clock cycle. But in our time they are considered obsolete and are now practically nowhere and in no circumstances used. More modern and most common is DDR2. It allows you to select 4 bits at a time. The module is executed in the form of a printed circuit board, which has 240 contacts (120 on each side). The standard supply voltage for it is 1.8 V. Relatively new is DDR3. It can sample in 8 bits of data per clock cycle. It is also made on a printed circuit board that has 230 contacts. But the standard supply voltage in this case is only 1.5 V. Also there is also DDR4, but this is a new technology, which is still very difficult to meet.
Throughput
Already we will finish the article about the latency of RAM. The one that was presented earlier is already enough to understand the bulk of information about the OP. And as a finishing touch - throughput. So, in an ideal value of this characteristic from the side of RAM should match the size of the parameter for the processor. Consider this issue, considering that we have the above mentioned dual-channel mode. We have a processor with a throughput of 10,600 MB / s. Then we can install the RAM module, the characteristics of which will be 5300 MB / s. In a pair they will provide the same size of bandwidth. But do not forget that the modules must be of the same frequency. And the best is that they also have the same volume, they were made by one manufacturer, and they were produced in the same batch. Then the latency of RAM will tend to the lowest possible value. If we talk about dual-channel mode, then specially for these cases, they sell Kit. This is what special sets are called, which are already optimized for this kind of work. It should be noted that you can use memory, the bandwidth of which is higher than that of the processor. But this will not significantly affect the latency, even if the difference is a multiple.
Conclusion
As you can see, the latency of RAM is a very important characteristic. Particularly pleasant is that it can be affected not only from the hardware side, but also by selecting the configuration for your computer. But at the same time it is necessary to keep within the reasonable and in more than four-channel mode not to work. No, of course, if there is a desire, you can also build a computer with 512 MB of RAM to boast a processing speed of 8 GB. But the effectiveness of such a move will be rather doubtful. It is better to stop in this case on 4 boards, each of which will have 2 GB.