New RAM standard - DDR4 RAM, characteristics and features. DDR3 vs DDR4

We checked what new DDR4 RAM modules differ from previously used DDR3 memory modules and how much more efficient they are than the previous generation of equipment.

First DDR4 memory information appeared in 2008. It was then assumed that it would hit stores within five years and very quickly gain more popularity than DDR3 memory.

It soon became clear, however, that the memory used had a very large potential for development, and a quick transition to a new standard did not make sense. Therefore, although several years ago computer companies showed their DDR4 memory models at various exhibitions, due to the lack of supporting platforms there was no possibility of its practical use. Everything has changed over the past year. DDR3 memory has reached its limit.

The end of the era of DDR3 memory

Although modules with DDR-2400, DDR-2800, and even faster frequencies are available on the market, further acceleration turned out to be almost impossible. True, some manufacturers managed to obtain higher clock speeds, but creating such memory modules on a mass scale was unprofitable and practically impossible.

Constant acceleration of the existing type of RAM is impractical - power consumption increases significantly and fault tolerance decreases. The solution to these problems turned out to be DDR4 memory modules, which have much more opportunities to increase performance, while consuming significantly less energy.

Do we need new DDR4 memory modules?

Yes, and not only because of the speed. The first memory models of the new type do not have greater performance than the previous generation modules.

When one technology reaches its limits and the other is just entering the market, we may not notice a difference in speed between them. In this case, it is not the performance that is important, but the prospects of the new technology. Therefore, now, when upgrading your computer, it is worth thinking about choosing a platform compatible with the new type of memory.

The next time we replace components, we will be able to use new generation modules. If after some time we realize that the memory used is too slow or insufficiently capacious, then we will not have problems purchasing more powerful components - otherwise the situation is in the case of DDR3 memory, which has reached its limit and will slowly leave the market.

One of strengths of DDR4 memory is its energy efficiency. Currently, the vast majority of computers sold are laptops, tablets and convertible devices. The most important feature of such equipment is its performance and operating time without recharging, which, in turn, depends specifically on energy consumption.

Is it worth changing the memory to DDR4?

For now, such a dilemma does not exist because a platform that supports both types of memory is not yet available. Therefore, replacing memory will result in replacing the entire platform. However, expect motherboards that support both memory types to be available soon.

Is it worth it then? change DDR3 memory to DDR4? If you are choosing a new computer with future upgrades in mind, it will be useful to consider this possibility. Of course, we will then spend more initially, but this will make upgrading the computer easier in the future.

New type of memory modules

Minor changes have occurred in the appearance of the memory module. True, its length and thickness are the same as in the case of DDR3, but an experienced eye will notice that the new modules are a millimeter taller and have 284 instead of 240 contacts.

In addition, the contacts in the central part of the module are higher than those at the edges. Thanks to this, installing memory requires less effort. The position of indents in the module has also changed. This procedure makes it impossible to place the memory in an unsuitable slot, such as one intended for installing DDR3 memory modules.

High speed DDR4

Currently, you can find mainly DDR3 memory on the market at frequencies of 1333 and 1600 M/s (million operations per second), and modules intended for enthusiasts reach frequencies of about 2400 or 2866 M/s.

In the case of DDR4, these parameters will be better, and operation at the level of 2400 M/s will become almost a standard. The JEDEC standard currently assumes the creation of DDR4 memory at speeds from 1600 to 3200 M/s, but modules at the 4166 M/s level have already been announced.

Long delays

Increasing memory speed always entails increasing latency, expressed in time cycles. A similar situation will happen this time. The JEDEC standard stipulates that the standard CAS latency for DDR4-2400 memory will be 15 cycles (for DDR3-1600 it was 10 cycles).

However, keep in mind that the delays do not actually change. To verify this, it is enough to make a simple calculation. A memory speed of 1600 M/s means its actual clock speed is 00 MHz. This means that one cycle lasts 1/800,000,0000 seconds. In this case, the delay expressed in 10 cycles is 12.5 nanoseconds. After performing the appropriate calculations for a 2400 M/s memory and 15 cycles, we get an identical result.

Large memory capacity

The largest DDR3 modules have a capacity of 8 GB. With DDR4 memory, a capacity of 32GB can easily be achieved. Assuming that a standard motherboard can accommodate four memory modules, this means that a computer equipped with 128GB of RAM will soon be a reality.

Performance difference

Even if there is a large difference in transfer speed between the two modules, in most programs there will be no or minimal change in performance.

It will only be possible to see the benefits of using faster memory if you use the most demanding applications and games.

Less energy consumption

DDR3 requires a voltage of 1.5V, while DDR4 only requires 1.2V. According to manufacturers, this voltage change should provide energy savings of 30%. In practice, the savings are somewhat lower, however, thanks to the use of several innovations, it was possible to achieve the desired floor.

Some help included changing the signaling type and using DBI, that is, the memory bus inversion method. It lies in the fact that if in a particular data line most of the information consists of zeros, they are replaced by ones, and the dedicated controller perceives the data line as upside down.

Thanks to this, it is possible to switch transistors off and on more rarely, which reduces energy consumption and improves signal stability.

The appearance of DDR4 RAM on the market shook the unshakable position of its predecessor. It has higher technical characteristics and many users have a logical question, which RAM strip is better? Numerous tests and comparisons of fourth generation RAM with DDR3 show what the difference is between them. When choosing a DDR3 memory module, keep in mind that it is not compatible with DDR4.

A computer is one of the components that is responsible for its performance: the speed of information processing and the maximum amount of data processed at a given moment. Until 2015, the first position was firmly held by third-generation DDR3 RAM, but with the advent of DDR4 the situation began to change towards the latest modification. The appearance of fourth-generation RAM caused a great stir in the computer equipment market, and at the same time a natural question arose, which is better than DDR3 or DDR4 and whether the appearance of the latter model is a regular marketing ploy?

History of DDR4 development

JEDEK began developing fourth-generation RAM back in 2005, when the most modern modification was DDR2. The company's engineers already realized at that time that the second generation of RAM would not be able to meet the requirements of rapidly developing processors and other PC components. Even the announced release of third-generation RAM will not be able to fully cope with the task. To solve the problem, simply improving data processing speed, as was done in DDR3, is not enough. It is necessary to take into account parameters such as power consumption and volume, which affect the throughput of the device.

Attention! To work with specialized programs: packages for three-dimensional design, photo or video editors, the main parameter for choosing RAM is its throughput, i.e. the speed of information processing.

In 2015, with the advent of Socket LGA1151 platforms on the market, PC users had the opportunity to conduct a comparative analysis of third and fourth generation RAM under the same conditions.

Specifications

Before you say that DDR3 or DDR4 is better and compare them, you should familiarize yourself in detail with their technical characteristics and capabilities, as well as their advantages and disadvantages. This approach will allow us to correctly and accurately determine the future of memory modules and identify a promising model.

DDR3

The main characteristics for RAM, regardless of its generation, are the following:

• Frequency. RAM of the third model is available with a frequency of 1066 MHz, 1333 MHz and 1600 MHz, and the latest modification has 1866 MHz. By overclocking the memory, its frequency can be increased to 2400 – 2666 MHz. The maximum value of this parameter during overclocking, which was obtained in laboratory conditions, is 4620 MHz.
• Voltage. Power consumption varies in the range of 1.5 - 1.8 V. The latest version of DDR3L is capable of operating at a low voltage of 1.25 - 1.35 V. The L index means Low Power.
• Downtime. To determine the performance of a memory stick, one of the important parameters is timings or latency (CL), i.e. the delay in the transfer of information. DDR3 1600 MHz has a latency of 9 clock cycles; it takes 1 second to obtain the temporary value. divide by 1600 million clock cycles and we get 0.625 ms per clock cycle. We multiply the result by 9 clock cycles and get 5.625 ns. Next, we multiply by 2 (the number of data transmission streams) and the latency is 11.25 ns.

Advice. The latency value can be determined from the RAM markings after the letters CL. Accordingly, the lower its value, the higher the performance of the device.

DDR4

The fourth generation RAM has higher technical specifications, due to which it outperforms its predecessor.

Comparison of DDR3 and DDR4

Based on the technical characteristics, it is clear that the latency of DDR4 is higher than that of its predecessor. However, when reading data linearly or storing it due to practically unchanged timings, this difference is compensated, and the RAM of the fourth model wins. When working in multi-threaded mode, due to lower latency, DDR3 wins within the limits of statistical error. When compressing large files (1.5 GB and larger), the time spent on the operation is 3% less for DDR4 than for DDR3. The third generation RAM specification provides for the use of Vddr voltage. When carrying out energy-intensive operations, it increases due to built-in converters, thereby generating abundant heat. The DDR4 module receives the required voltage from an external power supply (Vpp).

The RAM of the fourth model implements Pseudo-Open Draid technology; it completely eliminates current leakage, which was observed in the previous version, which uses Series-Stub Terminated Logic. The use of this interface for data input and output has reduced energy consumption by up to 30%. As for the memory capacity of the DDR4 bar, the minimum value is 4 GB, and for DDR3 it is optimal because the maximum is 8 GB. The third generation RAM structure allows for up to 8 memory banks with a line length of 2048 bytes. The latest modification of RAM has 16 banks and a line length of 512 bytes, which increases the speed of switching between lines and banks.

From a comparison of DDR3 and DDR4, we can conclude that the latest generation of RAM outperforms its predecessor in almost all respects, but this difference is little noticeable to the average user. DDR3L 1600 MHz in combination with Intel Core i5 is almost as good as DDR4. It is recommended to install fourth-generation RAM for modern games or work in specialized programs that require a large amount of memory and high data processing speed.

Comparison of DDR 3 and DDR 4 RAM: video

In order for modern games to run faster, the computer needs not only , but also a sufficient amount of RAM. Why is this necessary? Today's games have very large locations with a considerable number of objects, which are stored in the RAM. If there is not enough RAM, the game will access permanent memory and, if it is a slow HDD, the user will invariably receive freezes.

Corridor shooters may not require a lot of memory, but if you play large-scale RTS or FPS games, this makes a difference. For example, to play Battlefield 1, the manufacturer recommends using 16 GB of RAM or higher. If you have not yet decided how much RAM you need, use ours.

Samsung DDR4 2666 DIMM 8Gb

Probably, almost every user has heard about this sensational model from Samsung. Unfortunately, you won’t find a set of several planks, but nothing prevents you from buying one piece at a time and installing them together. In addition to its extremely low cost, this memory has excellent overclocking potential, which is why overclockers love this RAM. The stock speed here is only 2666 MHz, but without much difficulty on a good motherboard this module will take the frequency from 3200 to 3666 MHz, despite the fact that dual-rank memory usually runs worse than single-rank memory.

Advantages

Excellent overclocking potential
Very cheap
Very common in the market

Flaws

Appearance - couldn’t be simpler

Patriot Memory PV416G320C6K

If you don’t want to overclock, but your budget is very limited, then we recommend looking towards the Patriot Memory company. The factory overclocked kit has a frequency of 3200 MHz. If you want, you can, of course, try to squeeze more, but most likely you won’t succeed. The dual-rank memory PV416G320C6K will run at 3200 MHz only when the XMP profile is activated and the timings are increased. Out of the box you will only see a measly 2133 MHz.

In addition to the high frequency, the developers offer the user an interesting design that will fit well into the red assembly. In addition, it is possible to detach the radiator if suddenly you cannot install a tower cooler to cool the processor. The kit comes with a 10-year warranty!

Advantages

Low cost
High frequency with XMP profile support
Nice design
Detachable radiators
10 years warranty

Flaws

No specific memory chip vendor

Kingston HyperX HX432C16PB3K2/16

Kingston is one of the oldest memory manufacturers on the market. Its HyperX brand is aimed at gamers, and its products meet high quality standards. It is not surprising that the memory kit HyperX HX432C16PB3K2/16 A lifetime warranty is provided. Of course, this is not the cheapest option, but it still works out very well on a budget.

The operating memory frequency of this model is the same as the previous set - 3200 MHz with support for the XMP profile, but overclocking is much more stable. Apparently, this is precisely what the buyer overpays for when compared with Patriot Memory PV416G320C6K. It is also worth noting the traditional black aggressive style of Kingston.

Advantages

Lifetime Warranty
Stable overclocking
Interesting design

Flaws

Slightly overpriced

Patriot Memory PVS416G400C9K

If you own a processor from Ryzen, then you are probably looking at high-frequency memory that is overclocked from the factory. Patriot Viper brings to your attention the cheapest “whale” on the market, which will operate at 4000 MHz. Of course, in order to run the bars at such a frequency, you will need to dance with a tambourine for a long time in any case, but the performance gain is worth it. Please note that even the highest quality peer-to-peer models built on B-die chips will not always be able to reach the 400 MHz mark. So why pay extra for a brand then, right?

Advantages

Interesting design
High frequency from factory
B-die chips are often found
Low cost
Almost always in stock

We carried out a small express test of the operation of LGA1151 processors with memory, such as DDR3 and DDR4, last year, and this year we slightly expanded the studied area in the direction of budget models for this platform. In general, there was a feeling that the new type of memory does not have any performance advantages, but it does save some energy, which in recent years has become the main focus of Intel's efforts when developing new microarchitectures. True, we did not study the effect of memory on the power consumption of older models of Intel processors. And in general, their tests were carried out using the old testing methodology, and very different motherboards, etc., so the conclusions made last year may become outdated. Therefore, we decided to investigate the issue more carefully and in detail.

Test bench configuration

CPU	Intel Celeron G3900	Intel Pentium G4500T	Intel Core i3-6100	Intel Core i5-6400	Intel Core i7-6700K
Kernel name	Skylake	Skylake	Skylake	Skylake	Skylake
Production technology	14 nm	14 nm	14 nm	14 nm	14 nm
Core frequency std/max, GHz	2,8	3,0	3,7	2,7/3,3	4,0/4,2
Number of cores/threads	2/2	2/2	2/4	4/4	4/8
L1 cache (total), I/D, KB	64/64	64/64	64/64	128/128	128/128
L2 cache, KB	2×256	2×256	2×256	4×256	4×256
L3 (L4) cache, MiB	2	3	3	6	8
RAM	2×DDR3-1600 / 2×DDR4-2133	2×DDR3-1600 / 2×DDR4-2133	2×DDR3-1600 / 2×DDR4-2133	2×DDR3-1600 / 2×DDR4-2133	2×DDR3-1600 / 2×DDR4-2133
TDP, W	51	35	51	65	91
Graphic arts	HDG 510	HDG 530	HDG 530	HDG 530	HDG 530
Qty EU	12	23	23	24	24
Frequency std/max, MHz	350/950	350/950	350/1050	350/950	350/1150
Price	T-13475848	T-12874617	T-12874330	T-12873939	T-12794508

We used five processors, and two of them had already been tested earlier - which is why today we will use the results of the Pentium G4500T, and not the somewhat more relevant G4500/G4520 for retail buyers: the usual time savings. Still, we are most interested not in them, but in processors of a slightly higher class - for example, the younger ones in the Core i3-6100 and i5-6400 lines. Why the younger ones? It seems to us that it is these buyers who are most likely to want to save money when upgrading the system without changing the hardware from DDR3 to DDR4. And when buying a new system, the fact that at the moment budget boards with DDR3 support are slightly cheaper than their counterparts with DDR4 slots is most important for those who are assembling a budget computer. And if he can afford some Core i3-6320, then it would be better to “hold out” to the “real quad-core” Core i5-6400. But, nevertheless, we also couldn’t help but test the top-end Core i7-6700K together with DDR3 - after all, this is Intel’s fastest (and most power-hungry) offering for this platform, and therefore extremely necessary for assessing the maximum potential effect of switching to new memory standard.

As for the memory modules themselves, in both cases we used a pair of them with a total capacity of 8 GB. The frequency corresponded to that supported by the standard - 1600 MHz for DDR3 and 2133 MHz for DDR4. In principle, some motherboard manufacturers offer memory overclocking capabilities for DDR3, but there is one delicate point - to achieve high frequencies, the supply voltage is usually increased to 1.65 V (instead of the standard 1.5 V). At the same time, Intel has not recommended doing this since the days of LGA1156, warning that increased voltage can lead to damage to the processor. But officially, devices for LGA1151 are allowed to work not even with DDR3, but with DDR3L operating at a voltage of 1.35 V, i.e. for them this problem may be more pronounced. However, to be fair, over the past seven years we have never encountered processor failures, even when using “overclocker” modules. Moreover, we have not heard of situations in which it was possible to unambiguously declare the presence of such problems. But you know who saves the thrifty :) Moreover, various “high-end” modules with decorative radiators and other LEDs are still not suitable for the concept of minimizing the price of the system, since they are already more expensive than mass-produced DDR4. But the banal DDR3-1600 can still be useful.

Two motherboards were required. Ideally, of course, such testing should have been carried out on a universal model, three of which are already in ASRock’s assortment, but we haven’t gotten our hands on them yet. Therefore, we simply took two boards that were as similar as possible in design and even in purpose: ASRock Fatal1ty B150 Gaming K4 and Asus B150 Pro Gaming D3. And they are based on the same chipset, which can also be important, as well as a similar (ten-channel) processor power circuit.

Testing methodology

The technique is described in detail in a separate article. Let us briefly recall here that it is based on the following four pillars:

• Methodology for measuring power consumption when testing processors
• Methodology for monitoring power, temperature and processor load during testing

And detailed results of all tests are available in the form of a complete table with results (in Microsoft Excel 97-2003 format). In our articles, we use already processed data. This especially applies to application tests, where everything is normalized relative to the reference system (like last year, a laptop based on a Core i5-3317U with 4 GB of memory and a 128 GB SSD) and grouped by areas of application of the computer.

iXBT Application Benchmark 2016

The very first group of programs brought a surprise - on three out of five processors, DDR3 turned out to be faster than DDR4. Studying the detailed results shows that we have one program to “thank” for this, namely Adobe After Effects CC 2015. Its previous version, as I remember, spoiled a lot of blood for us due to its requirements for memory capacity (and depending on other hardware environment), Now here’s a new misfortune - and it’s related specifically to memory. On slow processors, however, it is imperceptible - there the confidence intervals of different measurements overlap significantly. But if it is possible to use four or more computation threads, the difference can no longer be attributed to error: on the Core i3-6100 and i5-6400 it exceeds 10%. And for the i7-6700K it decreases slightly: apparently, due to the larger cache memory capacity. In general, “progress” can sometimes turn out to be like that. Locally, the rest of the group's programs work on a system with DDR4 either the same or a little faster, which ultimately leads to almost equal results. For different types of memory, but not processors, of course, i.e., this is exactly the case when saving by saving old memory can allow you to purchase a faster processor, which will pay off handsomely.

In this case, on the contrary, we have some increase in results when using DDR4, and the faster the processor, the higher it is. But even in extreme cases it does not exceed 3%, i.e. it’s not worth rushing to change memory just because of performance.

Formally, the new memory is better, but in fact the difference of a fraction of a percent may be of interest only to fans of benchmarks, but not for practical use.

A similar case. No, of course, the results are consistently higher. But such an increase in performance cannot be recorded without a photo finish, so it is better to simply ignore it.

Again the differences are within 1%. Even where they exist at all. For buyers of entry-level systems, it makes even more sense not to worry, but to try to save money. Even when buying a new computer, you can still think about this, not to mention the case when a sufficient amount of DDR3 remains from the old one.

When packing the data, the Core i7-6700K still managed to heroically squeeze out as much as 2% of the difference due to the higher bandwidth. For the rest, DDR3-1600 is more than enough, and DDR4 may even get in the way due to still high latencies.

Over the last five years, file operations have been able to actively “load” memory, but in this case we are not inclined to attribute the effect to its performance. Rather, other third-party factors, such as the controller operating in the mode for which it is mainly designed.

Looking at the results of lower-end Intel processors, we felt that the higher latencies of DDR4 are generally contraindicated for this program. However, using faster models, you can see that as their performance increases, the requirements for memory bandwidth also increase. As a result, it is possible to “squeeze” up to 3-4%. Which, however, looks good only against the background of other groups of applications, but is too small for practical significance.

Ultimately, we come to almost complete equivalence of the two types of memory, since the difference between them is within the error. However, as we saw above, there are programs that “rigidly vote” for one of the options, but in such a strange way that it can generally be attributed to some kind of errors (or, what is the same thing, excessive and unnecessary optimization), which will be corrected over time. But it’s not even close that the results would increase by a third (in proportion to the effective frequency).

Energy consumption and energy efficiency

In order not to overdo it with the size of the diagrams, we decided to limit ourselves to three points - extreme and middle (the results of the other two systems can be viewed in the summary file). In principle, they demonstrate well why all this was started. And also the fact that for lower configurations the effect can, in principle, be neglected: some savings are also observed in the case of the Celeron G3900, but taking into account its very small “appetite” in general... Plus or minus five watts in a desktop system won't be a problem. 10-15 when using top processors is already something, but in relative terms it’s also not worth attention.

But, of course, it can bring a little moral satisfaction to a big fan of “greens.” Like LGA1151 in general - according to tests, even when using DDR3, it is still the most “energy efficient” desktop platform today, not inferior even to surrogate systems, but with incomparably higher performance. However, the LGA1150 was not bad in this capacity, and the “old” LGA1155, if its life was extended and there were no new developments, would have looked good. In fact, among desktop platforms there has been no competition in terms of energy efficiency for a long time. So the “strengthening and deepening” of work in this direction are echoes of events in completely different markets.

However, another question still remains unsolved, namely the effect of different types of memory on the power consumption of the processor itself. “Platform” efficiency is understandable: after all, the memory modules themselves have different power consumption. Does this directly affect the operation of the controller integrated into the processor? You can't tell in advance. For example, a discrete video card also “spoils” energy efficiency indicators, but does not directly affect the processor in any way. This means we need to measure. Moreover, this is not a problem for new platforms - since the days of LGA1150, the company has “transferred” the processor power system directly to a dedicated power supply line in its entirety.

As we see, there is an effect - more modest than for the “platform”, but it cannot be called loyal to the memory of the old type. Again, for younger models in Intel’s range it can be neglected, but for older ones you can get an extra ten watts “under the hood”. And this is even for standard DDR3 modules with a supply voltage of 1.5 V - increasing the latter (when trying to increase the memory frequency), of course, will only worsen the situation. Thus, the recommendation “not to raise” the supply voltage of memory modules can be trusted - this will not bring anything good. Bad, quite possibly, too. But let everyone decide for themselves whether to take risks or not. In any case, the impact of using DDR3 memory on the CPU's own power consumption (and, accordingly, heat dissipation) is a documented fact. As well as the small size of this “influence” in the case of processors in the budget segment. Or even mid-level models.

iXBT Game Benchmark 2016

In order not to overload the article with a large number of generally similar diagrams, we once again decided to make do with the integral score (remember: it does not reflect absolute indicators, but the ability of systems to somehow “pull” at least 30 frames per second in different games).

Actually, everything is obvious. Of course, higher memory bandwidth has a beneficial effect on the integrated GPU, but the situation cannot fundamentally change. In some places this allows, for example, to increase the frame rate from 28 to 31, which affects the overall result, but no wow effects are observed. This once again confirms that when purchasing a computer for gaming purposes, you need to “dance” from the video card. Then you can think about the processor, and everything else is up to your taste. If the money remains :) But the demands of modern (and even not so modern) games are such that they are unlikely to remain after the first step. So if using “old” memory allows you to purchase a slightly faster video card, you should definitely take advantage of it. And all attempts to improve the performance of integrated graphics without radical changes are not even worth the time spent, not to mention the money.

Total

So, we have clarified the previously obtained results and came to the conclusion that so far the effect of the transition to DDR4 is even more modest than it previously seemed. From which, however, it does not follow that this transition needs to be specifically counteracted in some way. First, the new memory saves some power. Moreover (which is also important) we are not only talking about greater efficiency of the entire system, but also the consumption of the processor turns out to be slightly lower, so the latter will work in a more gentle mode, and everything is easier to solve with cooling. Secondly, shipments of DDR3 are declining quite quickly, so this memory will certainly not become cheaper, unlike DDR4. To which we will have to switch sooner or later, and we will not be surprised if DDR3 support disappears over time and from new processors already within the LGA1151 framework. On the other hand, if you already have such memory, and in sufficient quantity, which is not planned to be increased in the near future, the moment of transition can be postponed until a more successful one financially. This will not pose any problems, even when purchasing a top-end processor, not to mention mid- and low-end devices. But, naturally, you should not get carried away with excessively increasing the voltage on the modules, since this has a certain negative impact on the processor.

Finally, it allowed us to compare memory of the DDR4 and DDR3 standards with each other under equal conditions. However, before moving on to the test results, we suggest that you first study the differences between these types of modules in more detail. This will give us a better idea of ​​what to expect from the new memory, not only now, but also in the near future.

The JEDEC association began developing the DDR4 standard back in 2005. At that time, stores were still selling DDR2 strips in full swing, and serial production of DDR3 modules was only planned. In other words, engineers already understood then that the capabilities of these standards are limited and sooner or later they will become limiting or not at all consistent with the level of other PC components.

Moreover, we are talking not only about memory bandwidth, but also about such important characteristics as the power consumption of modules and their volume. As you can see from this diagram, DDR4 strips outperform their predecessors in all respects.

Increased throughput

The throughput of the memory subsystem directly depends on the speed of the modules: the higher it is, the faster writing and reading from memory is performed. Of course, not all applications constantly exchange large amounts of data, so in real-life operating conditions the user may not experience the benefits of installing more powerful kits. But if we are talking about specialized programs like video and photo editors, CAD systems or tools for creating 3D animation, then the result from using high-speed modules will be much more significant. Also, high memory bandwidth is important when using integrated graphics. After all, the iGPU does not have access to fast GDDR5 chips, so all the information it needs is placed in the PC's RAM. Accordingly, in this case, installing more powerful memory kits will directly affect the number of FPS on the screen.

For the DDR3 format, the standard frequencies are from 1066 MHz to 1600 MHz, and only recently a value of 1866 MHz has been added. For DDR4, the minimum operating speed starts at 2133 MHz. Yes, you will say that DDR3 modules can make up the difference with overclocking. But the same thing is available for DDR4 strips, which have higher overclocking potential. After all, with the help of parameter optimization, DDR3 modules usually reach the level of 2400 - 2666 MHz, while DDR4 can easily reach heights of 2800 - 3000 MHz.

If we compare the DDR4 and DDR3 standards from the point of view of enthusiastic overclockers, then the advantage here will be on the side of DDR4. The value of 4838 MHz has already been reached, and only one year has passed since the announcement of the new format. Let us remember that the record overclocking frequency for DDR3 modules is 4620 MHz, which was recorded only 7 years after the launch of the DDR3 standard into production. In short, in terms of operating speed, DDR4 memory has very great potential.

Improved Energy Efficiency

The second important advantage of DDR4 modules is the ability to operate at low voltages. Thus, for their correct operation at nominal frequencies (2133 - 2400 MHz), only 1.2 V is enough, which is 20% less than their predecessors (1.5 V). True, over time, energy-efficient memory of the DDR3L and DDR3U standards with a supply voltage of 1.35 and 1.25 V, respectively, was introduced to the market. However, it is more expensive and has a number of limitations (as a rule, its frequency does not exceed 1600 MHz).

DDR4 memory also received support for new energy-saving technologies. For example, a DDR3 module uses only one voltage, Vddr, which is boosted using internal converters to perform some operations. This generates excess heat and reduces the overall efficiency of the memory subsystem. For the DDR4 standard bar, the specification provides for the possibility of obtaining this voltage (Vpp equal to 2.5 V) from an external power converter.

DDR4 memory also received an improved input/output interface called “Pseudo-Open Drain” (POD). It differs from the previously used Series-Stub Terminated Logic (SSTL) in the absence of current leakage at the level of memory cell drivers.

In general, the use of the entire range of energy efficient technologies should lead to a 30% gain in energy consumption. Perhaps, in the context of a desktop PC, this will seem like an insignificant saving, but if we are talking about portable devices (laptops, netbooks), then 30% is not such a small value.

Modernized structure

In the maximum configuration, the DDR3 chip contains 8 memory banks, while 16 banks are already available for DDR4. At the same time, the line length in the DDR3 chip structure is 2048 bytes, and in DDR4 - 512 bytes. As a result, the new type of memory allows you to quickly switch between banks and open arbitrary rows.

The DDR4 microarchitecture involves the use of 8-Gbit chips, while DDR3 modules are typically created on the basis of 4-Gbit chips. That is, with the same number of chips, we will get twice the volume. Today, the most common are 4 GB modules (by the way, this is the minimum capacity for a DDR4 memory stick). But in a number of foreign countries, more capacious modules are already offered: 8 and even 16 GB. Please note that we are talking about the mass market segment.

To solve highly specialized problems, you can create even larger modules without any problems. For these purposes, 16-gigabit chips and a special technology for their arrangement in a DRAM package (Through-silicon Via) are provided. For example, Samsung and SK Hynix have already presented sticks with capacities of 64 and 128 GB. Theoretically, the maximum capacity of one DDR4 module can be 512 GB. Although it is unlikely that we will ever see the practical implementation of such solutions, since their cost will be extremely high.

Despite the increase in all the main characteristics, the dimensions of the DDR4 and DDR3 memory sticks remained comparable: 133.35 x 31.25 mm versus 133.35 x 30.35 mm, respectively. In physical terms, only the location of the key and the number of contacts have changed (from 240 their number increased to 288). So, even with all the desire, a DDR4 module cannot be installed in a DDR3 memory slot and vice versa.

New communication interface with the memory controller

StandardDDR3

StandardDDR4

The new memory standard also provides for the use of a more advanced communication bus between modules and the memory controller. The DDR3 standard uses a Multi-Drop Bus interface with two channels. When using four slots at once, it turns out that two modules are connected to one channel, which does not have the best effect on the performance of the memory subsystem.

The DDR4 standard has improved this interface by using a more efficient scheme - one module per channel. The new type of bus is called Point-to-Point Bus. Parallel access to slots is definitely better than sequential access, since in the future it allows you to more effectively increase the performance of the entire subsystem. Users may not feel any particular advantage now, but in the future, when the volume of transmitted information increases, it will become more significant. After all, it was precisely according to the same scheme that GDDR video memory and the PCI Express interface developed. Only the use of parallel access made it possible to significantly increase their performance.

However, the Point-to-Point Bus imposes certain restrictions on the number of modules used. Thus, a two-channel controller can serve only two slots, and a four-channel controller can serve four. As the volume of DDR4 standard bars increases, this is not so critical, but it can still cause some inconvenience at first.

This problem is solved in a fairly simple way - by installing a special switch (Digital Switch) between the controller and the memory slots. Based on its operating principle, it resembles a PCI Express line switch. As a result, the user, as before, will have 4 or 8 slots available (depending on the platform level), while taking full advantage of the Point-to-Point Bus.

New error detection and correction mechanisms

Since working at high speeds with large data stacks increases the chance of errors, the developers of the DDR4 standard took care of implementing mechanisms to detect and prevent them. In particular, the new modules support the function of correcting errors associated with parity control of commands and addresses, as well as checking checksums before writing data to memory. On the side of the controller itself, it became possible to test connections without using initialization sequences.

Comparison of DDR4 and DDR3 memory performance in equal conditions

To conduct tests, we used the following bench configuration:

CPU	Intel Core i7-6700K (Socket LGA1151) @ 4.0 GHz
motherboards	ASUS MAXIMUS VIII GENE (DDR4) ASUS Z170-P D3 (DDR3)
RAM kits	DDR3L-1600 HyperX Fury HX316LC10FBK2/16 DDR3-2400 G.SKILL Ripjaws X F3-2400C11D-16GXM DDR4-2400 HyperX Fury HX424C15FBK2/16 DDR4-3200 KINGMAX Nano Gaming RAM GLOF63F-D8KAGA
Graphics adapter	Intel HD Graphics 530
HDD	Seagate Barracuda 7200.12 ST3500418AS
power unit	Seasonic X-660 (660 W)
operating system	Microsoft Windows 7 (64-bit version)

The primary goal of this experiment, of course, was to compare the capabilities of DDR4 and DDR3 memory kits at the same frequencies. To get a more objective picture, the test was carried out in the most popular operating modes of the memory subsystem: 1600 MHz, 2133 MHz and 2400 MHz:

Memory kit		Operating speed, MHz	Set of delays

In benchmarks that directly depend on the frequency of memory modules, both sets demonstrated comparable results in all modes. In most cases the difference was no more than 0.5%, so here there is parity between DDR4 and DDR3.

In tests that measure the latency when the processor reads data from memory and the speed of the PC in archiving-related tasks, the advantage was on the side of DDR3 standard modules. On average the difference was 4-5%. This gap is explained by the fact that DDR3 memory requires lower timings than DDR4 to operate at the same frequency.

Applications that are used to model objects and perform complex calculations respond better to increasing memory frequencies than to changing latency sets. Therefore, in this case, working at lower timings for DDR3 memory did not bring practically any dividends. At least, we are not inclined to consider an advantage at the level of 0.6 - 0.9% as an advantage that is worth paying serious attention to.

And now we come to the most interesting part - games. They were run on the Intel HD Graphics 530 graphics core built into the processor, since if you have a discrete video card, the RAM subsystem is far from the most decisive factor.

From the graphs presented above, the conclusion suggests itself that when assembling a PC with an integrated GPU, it is still better to give preference to the good old DDR3 format. Regardless of the selected mode (1600, 2133 or 2400 MHz), the advantage was on the side of DDR3 modules (4 - 10% depending on the game).

Summing up the intermediate results, we can confidently say that for assembling a desktop configuration, where the memory subsystem operates in standard modes, there is no point in purchasing DDR4 modules. They often show slightly lower performance than their DDR3 counterparts, and at the same time cost more.

But let's not forget that the new format has one more trump card in reserve - the ability to operate at higher frequencies. For example, today on the market you can easily find DDR4 memory modules operating in DDR4-3000 MHz or DDR4-3200 MHz mode, while DDR3 kits are usually limited to frequencies of 2400 and 2666 MHz. So theoretically, in this case, the advantage should already be on the side of the new type of memory.

At this stage of the experiment, the following memory sets were used:

Memory kit		Operating speed, MHz	Set of delays
DDR3-2400 G.SKILL Ripjaws X F3-2400C11D-16GXM (2 x 8 GB)

A series of tests carried out fully confirmed our assumption. The configuration with DDR4 memory operating in DDR4-3200 MHz mode turned out to be faster than the one with DDR3 modules running at 2400 MHz. The greatest performance increase was recorded in the AIDA64 benchmark: the speed of all main processes (reading, writing and copying data) increased by approximately 18 - 29%. The difference in other tests turned out to be not so significant (at the level of several percent), but it is still there. Thus, if you want to get the most out of your system, and the money spent to achieve this goal does not matter to you, then buying fast DDR4 modules looks like a completely justified idea.

True, the above applies only to programs. In games, the balance between frequency and latency is still critical. In this regard, DDR3 memory looks better, even if we are talking about a PC with integrated graphics. Therefore, when assembling purely gaming systems of any level, there is no point in overpaying for DDR4 memory. It would be more advisable to purchase a couple of DDR3 standard sticks, and use the money saved to purchase a faster video card, processor or SSD.

The last item in our testing was overclocking applications. Manufacturers of DDR4 memory modules very often mention overclocking enthusiasts in their advertising brochures. Therefore, we simply could not ignore this aspect. Testing was carried out in the popular overclocking discipline Super Pi 32M. The following memory kits were chosen as competitors:

Memory kit		Operating speed, MHz	Set of delays
DDR4-2400 HyperX Fury HX424C15FBK2/16 (2 x 8 GB)
DDR4-3200 KINGMAX Nano Gaming RAM GLOF63F-D8KAGA (2 x 4 GB)

Test results for DDR3 (left) and DDR4 (right) memory at 2400 MHz

Operating at the same frequency (2400 MHz), DDR3 and DDR4 memory modules demonstrated comparable results.

Test results for DDR4 memory at 3200 MHz

Replacing the DDR4-2400 HyperX Fury HX424C15FBK2/16 kit with the faster DDR4-3200 KINGMAX Nano Gaming RAM GLOF63F-D8KAGA allowed us to reduce the test time by about 7 seconds - a fairly large value by overclocker standards. So in this area, the advantage of DDR4 memory is beyond doubt. It seems that overclocking enthusiasts are primarily the main target audience of companies producing high-performance memory sets of the new standard.

conclusions

More than a year has passed since then, but, alas, the overall picture has not changed: the new standard has a lot of interesting innovations, but so far they have not been fully in demand in practice. For most real applications, the performance demonstrated by DDR3 standard modules is sufficient. Moreover, operating at the same frequencies, they even have a slight advantage due to the use of lower delays.

At least some benefit from DDR4 strips appears only when it comes to frequencies above 3000 MHz. After all, such values ​​are, as a rule, already unattainable for DDR3 standard kits, even when overclocked. True, whether those few extra percent of performance (in most games there will be no increase at all) are worth the overpayment is still a very big question.

AndSea Sonic Electronics for the equipment provided for the test bench.

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