Computer RAM Buying Guide

Computer RAM Buying Guide

Let’s start with a question: Do you want to upgrade your computer and you do not have enough money to buy a powerful graphics card or professional CPU? The simplest solution in such a situation is to upgrade the computer’s RAM. Upgrading RAM, while low cost, can have a tangible impact on overall computer performance and give you higher speeds. Until now, the use of 8 GB of RAM in computers was a minimum standard, and now with the introduction of new games, most manufacturers recommend the use of at least 16 GB. But choosing a good RAM is not just about determining its value. There are several factors involved in choosing a good RAM that can make you a better buyer. You should also pay attention to things like speed, latency and number of channels before buying, and this is where choosing a RAM becomes a bit difficult. By reading this shopping guide, you can buy Rome more consciously.

Size and structural form

There are two general structural forms of RAM, one called DIMM and the other called SO-DIMM. The two, despite their many technological and practical similarities, should not be confused. The main difference is in the size of these modules. DIMMs are larger and more elongated and are used in desktop computers. But SO-DIMM is smaller and is therefore used in All in One laptops and computers.

Types of RAM memory

RAMs come in a variety of forms and are recognizable by their DDR standard numbering. DDR standards, identified by the order of their numbers, have been introduced to DDR4, and each has improved over the previous generation. In general, each generation of DDR is faster than the previous generation, consumes less power and reduces latency. A limiting factor for the user is that not every generation of this memory can be used on a computer designed for the previous generation. Because DDR standards differ in the number of connection pins and the distance between the middle slot of the module. For example, in the DIMM model, we saw 204 pins in DDR3 RAM, and now the number of pins in desktop DDR4 RAMs has reached 288. Therefore, for a computer designed to use DDR3 RAM, you can not use DDR4 RAM. Every computer motherboard accepts only one type of this standard, and it is this motherboard that does not allow the use of different types. If you do not know what kind of memory is on your computer, you may be able to tell from the time of purchase of the computer:

DDR model: It was used in computers in 2002.

DDR2 model: was introduced in mid-2002 and has been used in computers ever since.

DDR3 model: has been used in computers since 2007 (2007) and has had the greatest influence in the computer market.

DDR4 model: was introduced in 2014 (2014) and is the fastest standard of this family so far.


RAM capacity and configuration

We are now living in an era where the use of three and four gigabytes of RAM in mobile phones has become natural. In such a situation, it is not at all strange that computers use 8 and 16 GB of RAM and even more. Now that RAMs are reasonably priced, it is no longer permissible to think about cost savings when buying RAM. Now, for a simple computer whose tasks are limited to opening a few text files and browsing the web, at least 8 GB of RAM is recommended. For those who want to build a computer for 3D modeling, editing or gaming purposes, the choice of less than 16 GB will not make sense. Some may be hesitant to choose between faster memory with less capacity and slower memory with more capacity. In such cases, it is better to put more capacity as the first priority and choose the memory with the maximum possible capacity.

In addition, you should pay attention to the number of channels on the agenda. In today’s market, we see single-channel, two-channel and four-channel rams, each with its own definition. In general, increasing the number of channels or using a multi-channel system in RAMs will increase the available bandwidth. In this way, RAM can move more data at any time. Instead of buying one high-capacity single-channel RAM, buy two half-capacity RAMs of the first model and use them in dual-channel mode.

Speed ​​and delay schedule

The speed of RAM is expressed in MHz and is not out of certain numbers. For example, between 2133 MHz and 2400 MHz, there is no other frequency, and your memory must have one of the valid frequencies. There are two types of representations for frequency that are actually equivalent and are converted to each other by a simple formula. For example, you may sometimes see the term DDR3-1600 and sometimes you may encounter PC3-12800. In these two expressions, the number that comes after DDR and PC refers to the type of memory module and the end number represents the frequency. In terms of DDR, the terminal number refers directly to the frequency (in MHz), and the number used in the PC display refers to the maximum data transfer rate in megabytes per second. The second number is obtained by multiplying the principal frequency by the number eight; That is, if you see a memory module that states the frequency with the phrase PC, quickly divide the prime number by eight to get to the original frequency. Regarding the frequency or the speed of RAM, it is important to pay attention to two points. The first is to always try to get the fastest memory, and the second is to make sure that the RAM frequency is compatible with the maximum frequency supported by your motherboard. All motherboard manufacturers declare the maximum supported frequency for their product RAM slots. If your RAM frequency is higher than the maximum frequency supported by your motherboard, the RAM will run at a slower speed than its original speed.

Another factor is the latency of RAM, which is represented by three- or four-digit expressions. Each of these numbers represents a specific type of delay, the most famous of which is the first. The first number is known as CAS Latency, which is denoted by the clock cycle and is denoted by CL. This delay time is actually the time between sending the command and executing it. There is a special relationship between memory latency and its speed, which is very important to understand. The higher the memory frequency and the shorter the latency, the better the memory performance. Many people only pay attention to the frequency and number of CL and find that the higher the frequency, the higher the number of CL. For this reason, some people think that due to the increase in CAS delay with increasing frequency, part of the declared speed is practically unattainable. But the truth is that with increasing frequency, the latency decreases or remains almost constant at worst.

The reason for this can be explained as follows: The number expressed for CL represents the number of hour cycles that take from the time the command is sent to its execution and is in no way related to the amount of time elapsed per second. Each clock cycle has its own specific time value in nanoseconds (ns), and the final latency must be obtained by multiplying the number of cycles by the time value of each cycle. The value of each cycle can be obtained by inverting the memory frequency; Because according to a physical law, the period is the inverse of the frequency. For example, if a DDR3 RAM is provided at 533 MHz and CL7, each clock cycle would be 1.533000000 seconds, which is equivalent to 1.87 nanoseconds. Now in this memory the real value of CAS is equal to 13.09 nanoseconds. If we want to make a simple comparison, consider another DDR4 RAM with a frequency of 800 MHz and CL9. In this memory, the value of each cycle will be 1.25 nanoseconds, and by multiplying it by 9, a delay of 11.25 nanoseconds will be obtained. You can see that despite the higher CL number in the DDR4 example, the actual latency was lower. This is because the initial frequency of DDR4 memory production is higher than that of DDR3s, which reduces the time value of each cycle.

Actual delay = number of clock cycles x time per clock cycle

The problem is that all RAM makers suffice to express the latency to the value of CL and write only this value on the memory. With CL, only one component of the above equation will be available, which cannot be used to determine the latency. If you want to judge the response speed of a memory module, you have to look at it from a nanosecond perspective. In the table below you can see an example of this fact and see how a module with more CL may have less latency. Now what is the result of all this talk? Surely the question has arisen for you, how can one finally choose one of the available RAM modules? Our advice is to pay attention only to the MHz speed and choose the highest frequency that matches your pocket. Rest assured that as the frequency increases, the actual latency remains virtually unchanged.

Now that you understand the difference between different types of RAM and your understanding of frequency and time latency, choosing a good RAM is no longer a difficult task. Just pay attention to your needs and choose a good model from a reputable manufacturer for yourself. Remember that more capacity is always better than more speed. Most of the capacity is the undisputed king of the Roman world.