Let us remind you that you can choose RAM for a PC or laptop according to a variety of criteria, including memory generation and its clock frequency, in the general catalog. And if you want DDR5, then first you should make sure that your CPU supports it. Also, when choosing graphics cards, potential buyers have the opportunity to filter models by GDDR type.

The origins of memory — SDRAM and VRAM

The start of the modern era of RAM was preceded by the release in 1996 of such a variety as SDRAM. This is an abbreviation for Synchronous Dynamic Random Access Memory, which essentially means that the operation of RAM became not only dynamic, but also synchronous. At the same time, all key memory components began to operate at the same frequency, rather than asynchronously as before.

At the time of its introduction, SDRAM was quite expensive. It was first used in premium graphics cards of that time, i.e. it debuted on the market as SDR VRAM.

The operating frequency of SDRAM ranged from 66 to 133 MHz, and the voltage was 3.3 V. Bandwidth did not exceed 1 GB/s, in addition, such a DRAM lacked support for multi-channel mode, that is, several sticks did not allow to raise the bandwidth. Video memory based on SDR had slightly increased frequencies (up to 183 MHz), and increased to 128 bits of the bus provides bandwidth of 2.8 GB/s.

Before DDR, both frequencies and memory capacities were low.

In 2000, DDR entered the mass market, and even earlier (in 1999) — GDDR. This was the debut of a new technology, which today is the basis for current developments.

RAM evolution from DDR to DDR5

The prototype of a new type of DDR was created by Samsung in 1997, and the complete working chip was presented in 1998. But the release of components to the masses occurred 2 years later, when motherboards with DDR support debuted.

This type of RAM was based on SDRAM, but the creators changed the mechanics of reading commands. The main innovation partly becomes clear from the decoding of the name — Double Data Rate: there is a doubling of the transfer rate, because the data is read twice per clock. This technology is also called 2n-prefetch.

Interestingly, the physical frequency of memory operation against SDRAM has not changed, but the amount of data transferred has increased by 2 times. In this regard, the concept of effective MHz appeared. Thus, in DDR it is the corresponding parameter that has become the main characteristic. Real 133 MHz (as in the predecessor of SDRAM) provided effective 266 MHz in DDR.

Briefly about the main performance characteristics of DDR:

  • the real frequency was no longer mentioned;
  • the effective frequency ranged from 266 to 700 MHz (but most often up to 400 MHz);
  • typical voltage 2.5 V;
  • performance 3.2 GB/s (and up to 5.6 GB/s when overclocked) per channel;
  • support for dual-channel mode, meaning bandwidth is increased with two sticks.
The appearance of DDR sticks of different generations does not differ very much.

DDR2 debuts in 2003. In the second generation, they implemented the ability to transmit 4 bits per clock (4n-prefetch technology). This was achieved by increasing the frequency characteristics of the bus and buffer.

Let's look at a specific example. In a DDR1 chip with a real frequency of 200 MHz, all components operate at these values. Effective frequency characteristics reach 400 MHz (due to 2n-prefetch). In DDR2 with the same 200 MHz, the bus and buffer function at double the frequency of 400 MHz, so that the final effective value for the module is 800 MHz.

As a result, the performance increased significantly, but the latency also increased in the same way, so at first DDR2 did not give a tangible performance gain. The situation changed with the release of new generations of CPUs - AMD Athlon X2 and Intel Core 2. By the way, even today the full potential of advanced RAM standards can be fully disclosed by the controllers adapted for them.

Main parameters of DDR2:

  • frequencies up to 1200 MHz;
  • operating voltage from 1.8 to 2.1 V;
  • bandwidth up to 9.6 GB/s.

In 2007, DDR3 was released. The increase in effective frequency was realized in the same way - data began to be transferred 8 times per clock (8n-prefetch). This was ensured by another doubling of the bus and memory buffer frequencies, while the core, as before, worked in the range of real values from 100 to 266 MHz. Initially, DDR3 had the same problems — high timings and, as a consequence, insignificant performance gain. The situation was corrected by Intel's new controllers on the LGA1366 platform, where a 3-channel memory controller appeared.

Another innovation of the third generation of RAM is the Extreme Memory Profile (XMP) function, which provides support for overclocking frequency characteristics.

Main differences of DDR3:

  • frequency up to 1866 MHz, and with XMP — up to 2933 MHz;
  • typical voltage 1.5 V;
  • performance up to 23.4 GB/s per channel.
DDR3 RAM

3 years later, the DDR3L standard was officially released, the main difference of which was the reduced voltage (1.35 V). This type of RAM was first used only in ultrabooks, but since 2013 it has been used in a wide variety of laptops and PCs. By the way, both types of DDR3 are on sale at the time of publication of this article.

In 2014, the fourth generation of RAM — DDR4 — entered the market. The engineers decided to avoid the practice of further increasing the bus frequency, but optimized data access: information is taken from two memory banks instead of one, and then combined into one stream. In essence, this is 8n-prefetch, but with increased frequencies and lower operating voltage.

One of the features of DDR3 has become _legal_ overclocking with the XMP function.

The widespread adoption of DDR4 commenced in 2015, yet a significant performance leap compared to the third generation was not immediately apparent, primarily due to a renewed increase in latency. The true capabilities of this DRAM type only became evident upon the launch of more advanced computing platforms, namely the AMD AM4 and Intel LGA1151 v2.

Main characteristics of the fourth generation DDR:

  • frequencies — up to 3200 MHz (and up to 5000 MHz with XMP overclocking);
  • operating voltage 1.2 V (with overclocking — higher);
  • bandwidth up to 40 GB/s.
DDR4 RAM

It should be noted that with the increase of multi-core CPUs, the increase in RAM bandwidth per core was practically absent. And many memory controllers were not ready for the peak frequency characteristics of DDR4, which resulted in the appearance of dividers that allow the processor to work with half the frequency of the stick.

It would seem that the development of controllers clearly does not keep up with RAM technologies and are just beginning to reveal the full potential of the fourth generation, but DDR5 will debut in 2021. There are several significant changes taking place here:

DDR5 has become faster and more energy efficient.

  • This RAM is capable of transferring data not 8, but 16 times per clock (16n-prefetch).
  • Instead of a standard 64-bit bus, a pair of 32-bit channels is used, which makes it possible to perform more tasks in parallel.
  • It achieves up to 128 GB of memory per stick, while DDR4 has a maximum of 32 GB.
  • Each module has error correction (ECC) implemented by default, which in earlier generations only occurred in server RAM.

Main characteristics of the DDR5:

  • frequencies start from 4800 MHz;
  • typical voltage 1.1 V;
  • performance per channel up to 65.6 GB/s.
DDR5 RAM

One must keep in mind that DDR5 is still evolving. It is expected that the effective frequencies may exceed 12000 MHz as well, although there are 8000 MHz sticks available for early 2024. Bandwidth should also increase.

For clarity, the differences between SDRAM and the main generations of DDR are summarized in the table:

Generation Released Effective frequency (max), MHz Amount of data per clock, bits Bandwidth (max), GB/s
SDRAM 1996 133 1 1
DDR 2000 700 2 5.6
DDR2 2003 1200 4 9.6
DDR3 2007 2933 8 23.4
DDR4 2014 5000 8 40
DDR5 2021 8000 for now 16 65.6 for now

VRAM evolution from GDDR to GDDR6

In parallel with the RAM evolution, video memory technologies are also improving. Its key design difference is its location on the graphics card (physical soldering) and the ability to increase the bus width.

GDDR debuted in 1999 and worked similarly to DDR, transferring two bits per clock cycle. True, thanks to optimization, the frequencies were higher, up to 900 MHz. Also, the bus width of top-end graphics cards with GDDR was 256 bits, so the bandwidth reached 30.4 GB/s.

In 2003, GDDR2 was released, which was not fundamentally different from the first generation. The main change is the increase in effective frequencies to 1000 MHz and the ability to provide a bandwidth of 32 GB/s in flagship graphics cards.

VRAM is also actively evolving and even ahead of RAM in some ways.

The second generation of graphics memory was not very popular, because in 2004 GDDR3 was released. This variety is based on DDR2, which means that it is capable of transmitting data 4 times per clock. The maximum frequencies reached 2500 MHz, which provided a PS of 70 GB/s. And the record at that time graphics performance gave graphics cards of NVIDIA GeForce GTX200 series. They received a bus width of 512 bits, and the bandwidth amounted to 159 GB/s.

GDDR4 video memory was introduced in 2006. It is based on the technologies used in DDR3, in other words, 8n-prefetch. But in practice neither by effective frequencies, nor by bandwidth the 4th generation has not left GDDR3. Moreover, its predecessors even outperformed this graphics memory. The maximum from GDDR4 is 2250 MHz and 128 GB/s respectively.

Graphics cards with GDDR5

The new generation didn't wait long either — GDDR5 was released in 2008. Here an important innovation was added to the 8n-prefetch technology — parallel transmission of two signals at once. Technically, instead of double data rate there was a fourfold increase (Quad Data Rate), and the number of transmitted bits per clock rose to 16. A similar development became the norm for new generations. GDDR5 has been the market leader for a long time and has not lost its relevance today. Due to new technical processes, frequencies have risen to 9000 MHz, and performance on flagship cards with a 512-bit bus has reached 336 GB/s.

In 2016, for the first time, video memory acquired the latest technologies. Thus, GDDR5X received support for 16n-prefetch along with Quad Data Rate, so that data can be transferred 32 times per cycle. But the real performance gain was not large compared to GDDR5, since in order to avoid overheating it was necessary to reduce the core frequency. Total top indicators were 11400 MHz and 547 GB/s. GDDR5X did not become very popular, because a new generation came out quite quickly.

In fact, modern video memory is no longer DDR, but QDR (Quad Data Rate).

GDDR6 video memory debuted in 2018. There were no critical innovations here, but the memory channel was divided in half, which allowed to perform more parallel requests and better cope with resource-intensive tasks, and without increased temperatures. Effective frequencies rose up to 20000 MHz, and the top cards reached a bandwidth of 960 GB/s (at 384-bit bus). GDDR6 is the current 2024 memory used on GeForce RTX 3000 and 4000 series, as well as on flagship AMD Radeon.

Graphics cards with GDDR6

GDDR6X is the latest version of video memory, which is an improvement on the 6th generation. It appeared in 2020. The 4-level PAM4 encoding technology was implemented here, which in theory allows you to transmit not 32, but 64 bits per clock cycle. But so far the real advantages compared to its predecessor are not impressive — the effective frequency has increased to 22400 MHz, and the bandwidth has increased to 1000 GB/s. True, both GDDR6 and GDDR6X are still developing and can reach new records.

The main differences between video memory generations are summarized in a comparative visual table:

Generation Released Effective frequency (max), MHz Amount of data per clock, bits Bandwidth, GB/s
GDDR 1999 950 2 30.4
GDDR2 2003 1000 2 32
GDDR3 2004 2484 4 159
GDDR4 2006 2250 8 128
GDDR5 2008 9000 16 384
GDDR5X 2016 11400 32 547
GDDR5 2018 20000 for now 32 960 for now
GDDR6X 2020 22400 for now 54 1000 for now

Memory development outlook: competition from HBM, DDR6 announcement

In parallel with DDR and GDDR, another technology HBM — High Bandwidth Memory — is evolving. This is a multilayer variety of memory, which is located not on the board, but on the substrate of a computing or graphics chip. HBM was close to the "stone", which allows you to expand the interface of interaction, up to buses for 5120 bits. As a result, the final bandwidth is higher at lower frequencies than the main competitors (the maximum here is 6400 MHz in the third generation).

If DDR is like a cottage community, then HBM is a skyscraper.

HBM video memory is used in server and professional graphics adapters, while in gaming cards it is more reasonable (and cheaper) to use GDDR. So far, the newest is the third generation of memory. But in the second quarter of 2024 the first accelerated computing from Nvidia with a new version of HBM3e should be released. For her declared bandwidth of 4080 GB/s (and theoretically it can reach 7066 GB/s).

Samsung has already announced the 6th generation of DDR.

DDR and GDDR also continue to be evolved. Samsung announced both DDR6 development and GDDR6W video memory upgrade. Commercial realization of a new kind of RAM should be expected not earlier than 2025 (and more likely even later). It is assumed that the effective frequency will be 12,800 MHz with overclocking capabilities. GDDR6W with a reduction in overall sizes will increase frequency characteristics (although, apparently, not significantly) and will be an increase in bandwidth up to 1400 GB/s.

But these promising varieties will not soon become widespread. So far, both DDR4 in RAM and GDDR5 in cards are widely represented.

Conclusions and recommendations for selection

It can be unequivocally stated that the development of RAM is ahead of other hardware. DDR5 sticks appeared more than 2 years ago, but there are not very many CPUs supporting them yet. And when choosing graphics cards, gamers feel free to choose models with GDDR5. This generation has been on the market for 15 years, for a second, but it’s still relevant.

In general, if you already have a PC that needs to be modernized, the fifth generation of RAM is an ambiguous choice: most likely, you will have to change almost the entire system. For a new assembly in 2024, you can look towards DDR5, especially if you are ready to pay extra. Firstly, the fifth generation is noticeably superior to the fourth one both in terms of effective frequencies and bandwidth. Secondly, the price difference with DDR4 is slowly decreasing.