How to choose RAM: options and recommendations

It is well known that memory plays the role of intermediary between the hard drive and processor. It stores the current data previously loaded from HDD or SSD, you will need the processor in a certain period of time. Why not get rid of the intermediary? — you ask. After all this we will give the opportunity to the processor and hard drive to exchange information and to work with program files directly — bypassing the RAM, and the question of how to choose RAM for a computer in this case is not relevant.

However, if you exclude the RAM from the hardware configuration, we will inevitably face with the problem associated with the speed of your computer. No matter how far stepped IT, but so far all SDD and HDD drives are a lot slower than RAM and accordingly inferior in speed. For this reason, it is necessary first to load different data in the faster memory that the CPU was not idle without business, and could in the moment to quickly get all the necessary information for normal operation.

Before proceeding to the choice of RAM, let no technical subtleties, let us examine the principle of its operation two simple modeling of the situation.

Suppose that you started the program, worked in it, and then closed it and launched the game. In this case, the data associated with the program will be unloaded from RAM, and the information associated with the game loaded in RAM. Therefore, the processor will quickly receive all the necessary information to perform calculations related to the game.

For example, on your computer simultaneously run multiple demanding computer programs, the type of three-dimensional graphics editor, non-linear video editor or a media Converter. If the amount of RAM will be enough, then all the data required for the processing of these applications will be loaded into RAM. Depending on what program you switch to operate the processor to apply particularly to those memory cells where the data is stored associated with this program.

For the record we should say that the processor interacts with memory is not directly but via a special chip located on the motherboard. In IT circles it is called the North bridge. In turn, the processor (CPU), North bridge and a storage device operatively connected by a very thin conductors which are routes and therefore they are called system bus.

At the technical level things are much more complicated, but the goal was to explain to the uninformed why we need RAM in the computer and how it plays a role. Before we dig in to the selection of RAM and sharpen its focus on its parameters, I suggest to read this study.

Testing RAM memory on 4, 8 and 16 GB.

If you are one of those who think that lots of RAM doesn't happen, then take more and more expensive and don't read any further. If you to the choice of RAM I wish to be prudent and not ready to pay more money, but want to get the expected result, then immerse yourself in the process. At first glance, to choose RAM for your existing or future computer configuration is quite simple, but still there are some nuances.

Suppose that some people are limited in the budget, and informed the assembled system unit on Board is:

  • CPU: Intel Core i7-6700K (4.0 GHz — 4.2 GHz)
  • Graphics card: GeForce GTX 980
  • SSD: Crucial MX200 1 TB
  • Power supply: SilverStone Essential Gold 750w
  • RAM — DDR4-2666 at 4, 8 and 16 GB (tested three options)
  • the Windows 10 Pro 64-bit

And here in simple layman there is a dilemma how much RAM to put on this Assembly and not to overpay for the amount of memory that eventually will be claimed. Can be 4, 8, 16 or 32 GB. How much RAM in the end will justify itself? According to studies by Stephen Walton (Steven Walton — the editor of the portal [urlspan]TechSpot[/urlspan]) RAM 16 GB justified in two situations, in other cases, enough, and 8 GB.

All this configuration was performed more than 10 tests using RAM DDR4-2666 at 4, 8 and 16 Gigabytes. Test with large amount of RAM was justified in rendering a 17 minute video in Adobe Premier. The same video has done it all, but for a different period of time. 16GB — 290 seconds 8GB — 300 seconds 4GB — 415 seconds.

Test to compare the performance during file compression, showed that the amount of RAM it plays a significant role. Speed of execution was as follows: 16 GB — 9 290 MIPS (million operations per second), 8 GB — 2 902 MIPS, 4 GB — 446 MIPS.

In the remaining tests in this Assembly, the internal memory 8 and 16 GB ceteris paribus proved almost the same, but the 4 GB memory on all fronts has given way slightly.

Under the three tests, GTA V, Batman: Arkham Knight 2015 and F1 showed the same FPS (frames per second). In my opinion testing is carried out efficiently, but research in the field of games surprised me a little. I do not in any case do not put test game in question, but I believe that the game was tested on minimal requirements, despite the inherent potential in the components and the Assembly as a whole. In my opinion for gaming and most tasks enough 8 Gigabytes, but if you do video processing or 3D modeling, I would recommend to put at least 16 GB of RAM.

what do the settings of the computer's memory.

The acronym RAM (random access memory) in English sounds like RAM (Random Access Memory). RAM is volatile. That is, once you shut down the computer or in the house to suspend the supply of electricity, all the data from it disappears. However, when you put the computer into sleep mode, activate hibernation (power saving mode) data is stored in a designated area on the HDD or SSD disk, and the electricity supply is also stopped.

However, in this case, the inclusion of computer data will be restored in memory from a previously saved region, and you can continue where you stopped because all previously running apps continue to work. However, this information is desired for the picture and it is time to consider types and features RAM.

the Type of memory. The developers of RAM constantly strive to make it more fast and efficient. In consequence of this RAM one generation replaces another. At the moment there are types of memory (or modules in which they are implemented) DDR, DDR2, DDR3 and DDR4. The first two have already sunk into oblivion and lost its relevance, and the second two at full speed are used in the Assembly of the computer.

Each new generation of RAM is in all respects superior to the previous one and is not interchangeable electrical and physical parameters. Memory is formed on a so-called module (PCB) with a special cut (key), which should match the existing wall in the slot on the motherboard.

This is done in order to physically no one could install the module of the same type in a slot designed for another type of memory. For example, you cannot install DDR3 into a slot designed for DDR4 because of the different location of the key in the row of contact groups and Vice versa. The power consumption of the memory modules differ. Depending on the generation they work under the following voltage:

  • DDR — 2.5 V;
  • DDR2 — 1.8 V;
  • DDR3 — 1.5 V (DDR3L exists — 1.35 V. Low-power saver);
  • DDR4 — 1.2 V;

The lower the consumption, the lower the dissipation. Because the DDR of the third and fourth generation have low power consumption, the radiator cooling it straps to anything, unless you are overclocking.

Bandwidth. In fact, the bandwidth determines the maximum amount of data can be transmitted on the channel per unit time (one second). Since the fastest component is the CPU, the task productivity of the computer in General is reduced not only to increase the clock frequency of the processor core, and more to increase the speed of other devices. Memory in this sense is faster than the other components but a slower processor. As the performance of the CPU depends on the bitness of the system bus and the performance of the RAM depends on the bitness of the memory bus.

This parameter is very important because it affects the performance of your computer in General. For optimal operation, the throughput of the memory bus should match the throughput of the bus of processor. What I'm saying? For example, we want to build a computer and we already have a motherboard with a connector for Intel (Socket 1151) with unsoldered slots for DDR4. We have already bought the appropriate RAM GeIL DDR4-2133 32768MB PC4-17064 (Kit of 2×16384) and left to pick up the CPU.

In our case, the bandwidth of a single module of RAM is 17064 MB/s. Since we have two modules, then this parameter must be multiplied by two (2 x 17064 =34128 MB/s). Therefore, it is desirable to select a processor that supports such memory bandwidth. Since online stores are the information not in full, I recommend to open the official site of Intel and to consult the specifications of the processor.

Note the line «the Maximum memory bandwidth» where we are interested in parameter must correspond to a previously received us value for RAM (34128 MB/s). We know that 1 Gigabyte (GB) is equal 1024 megabytes (MB). Therefore, subject to rounding, Intel Core i7-6700K with a value of 34.1 GB/s equals 34100 MB/s. In the specification of processor throughput for memory include two modules, as evidenced by the support for two memory channels (Max. the number of memory channels: 2).

Since we are using two memory modules, then we will activate dual-channel mode, which will give us twice the throughput. Looking ahead to say that to enable dual channel mode is better to use ready-made sets of two or more strips from the same manufacturer with the same clock frequency, and memory timings. Sets of RAM manufacturers are tested for compatibility, but you can pick up the planks themselves, but in this case there is no guarantee of the absence of critical errors during operation.

To activate dual-channel mode, strap the RAM on the motherboard should be placed in certain slots. Usually they are one color and the insert strips should be 1 and 3 or 2 and 4 slot. In games dual-channel mode will give a slight increase of 1-3%, but the program will get the performance up to 30%.

Frequency. This option is under the scrutiny of people interested in crackdown (Overclockers). The frequency of the memory is measured in Hertz and describes the number of cycles (trips) per unit time (1 second). The parameter RAM must match the supported frequency of your motherboard. What do I mean? Suppose you decided to buy memory standard DDR4 effective clock frequency of 3200 MHz, and your existing motherboard supports DDR4, but with a clock frequency of not more than 2133 MHz.

In this case the memory module when the opportunities will run at a frequency of 2133 MHz and so the bandwidth will be lower. Along with this, other things being equal (same build of iron with the same screen resolution) in the gameplay you won't notice a significant difference.

For example, between DDR3 1333 MHz and 1600 MHz or between memory 1866 MHz and 2133 MHz increase FPS (frames per second) on average will be 1%. Memory modules with high clock frequency will noticeably reveal themselves when you back up data when working in specialized programs for editing video and other multimedia content. Technically, it so happened that the modules with higher frequency have higher timings (delays). For games less than the time delay of the signal, the better.

Latency (timing). It is obvious that to increase maximum throughput in the RAM need to increase the frequency of its work. However, in addition to frequency, the memory is characterized by the system timing. In fact, this parameter determines the time delay in cycles and the order of the memory access begins with the control registers. After activating the necessary memory banks (there is enter the address of the string and supply the synchronizing signal RAS) and the arrival of a positive clock pulse opens the access to the necessary line.

In turn, the address of the string is placed in a special address buffer of the string and held there the required amount of time. After some period of time (referred to as the RAS to CAS delay) is the delay in clock cycles of the signal relative to CAS, RAS. After the pulse from the CAS and the arrival of a positive clock pulse is sampling the column address present in the moment, on the address bus. After this, the access to the necessary column in the memory matrix.

After a certain time CAS Latency, the data bus appears the necessary information, which can be already accepted for processing by the processor. Each subsequent information appearing on the data bus in the next clock cycle, is characterized by the length of the batch cycle. It completes a series of accesses to memory Bank a dedicated team to deactivate RAS Prechrge. This command is available for one or two cycles before the last data.

Referred to periods of time RAS to CAS delay (tRCD), CAS latency (tCL), RAS Pre-charge (tRP) are the memory timings and are recorded in sequence. For example, 5-5-5-15; 9-9-9-24; 11-13-14-32. From a technical point of view it is a very complex process, but it is important to understand is that the smaller the timings, the more rapid is the memory, and the increase in frequency inevitably leads to the increase in timings.

However, with each generation of DDR memory manufacturers increase the clock speed and as a consequence grow the timings. However, the performance of the RAM grows and kompensiruet this increase in clock frequency. To put it simply, the time to retrieve data from the RAM increased, but proportionately increased and the data packet issued by the bus processor single cycle.

The memory modules of the same generation (e.g. DDR3), with different frequencies and timings will not prevail over each other, for example games. Despite the significant difference in the frequency and timings between DDR 3 and DDR4, the performance will be greater because it uses different technology.

Volume. Many users, this setting is admired and associated with the fact that the more the better. Some truth in this of course there are, but independent testing, conducted by Steven Walton talking about the fact that if you are not running demanding programs such as Adobe Premier, you will be enough total memory capacity of 8 GB.

Simple rules and recommendations for choosing the RAM.

In this block, instead of summarizing, I decided to summarize the information concerning the selection and installation of RAM.

  1. If you are building a computer with «zero», I recommend to give preference to DDR4 (performance is higher and power consumption is lower), because you will still buy a new motherboard. If you are trying to upgrade an existing computer of the previous generation and you at the same time there are a few laths DDR3 or DDR3L, in order to save costs to think about buying a motherboard with a soldered slots for this memory type.
  2. The apparent advantage of the DDR4 standard is the fact that, technically, the manufacturers have the opportunity to create modules of a large capacity (up to 128GB). However, when assembling the computer, do not mindlessly chase the memory that start from the assigned tasks. Better the money saved add the total allocated budget to the graphics card.
  3. If you are not going to overclock and increase operational conditions (voltage, frequency) memory, the modules with large heat sinks and coolers for you to anything. Send money in the Treasury to the graphics card or put on the SSD.
  4. Give preference to sets Kit (2, 4 modules included), where memory modules have the same timings, capacity and frequency. The kits were tested from the same manufacturer and guaranteed operation in dual channel mode.
  5. At the time of unpacking, transfer or installation of the module, hold the bar over the ends to prevent damage to the low voltage of the elements by static electricity. When you transfer the module to another person, you need to put the bar, and let him take it. During transfer of the memory module of the hands may occur static electricity. Remember the saying: «Times a year and stick shoots».
  6. Choose RAM from a reputable manufacturer. There are only a few companies, Samsung, Hynix, Micron and Toshiba produce chips for memory and by and large all manufacturers of RAM modules purchased from them. However, it is well proved in the market of manufacturers of laths of the RAM with Kingston and Corsair GOODRAM.
  7. In conclusion, let me remind you that 32 bit operating systems of the Windows family do not see memory greater than 3 Gigabytes and, accordingly, will not be able to interact. Therefore, if the computer is physically installed more than 3 Gigabytes of memory, use 64-bit operating system.

I would be grateful for additions and constructive comments concerning the choice of RAM.

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