DDR5 (short for Double Data Rate 5) is the next-generation standard for SDRAM (Synchronous Dynamic Random-Access Memory). It is designed to deliver much higher performance while consuming less power than its predecessor DDR4.
Below, we have covered some of the most common questions regarding the latest memory arrival. How fast DDR5 is? What are its benefits over DDR4 RAM? When it will be available?
But let’s start with a basic question: Why do we need DDR5 RAM?
With the 3rd generation Zen 2 Ryzen processors, AMD has released an all-new architecture with improvements to core count, clock speed and instruction per clock. The company has put 6-core processors at the mid-range and 12-core at the high-end.
In 2019, AMD released 16-core Ryzen 9 3900x and 3950X CPUs, doubling the thread count of its competitor Intel i9-9900 series chips.
Bandwidth per core has been declining since 2018 | Credit: Micron
If our desktops are going to keep up with Intel and AMD’s core war, we will need to significantly increase the memory bandwidth per core.
DDR5 Vs DDR4: Improvements
Following are the five most significant specification advancement made to DDR5 RAM –
|Speed||1600 to 3200 MT/s data rate
0.8 to 1.6 GHz clock rate
|3200 to 6400 MT/s data rate
1.6 to 3.2 GHz clock rate
|I/O Voltage||1.2 V||1.1 V|
|Channel Architecture||72-bit data channel (64 data + 8 ECC)
1 channel per DIMM
|40-bit data channel (32 data + 8 ECC)
2 channels per DIMM
|Dram Size||16 GB||32 GB|
1. More Speed
While DDR4 supports a maximum data rate of 3,200 megatransfers per second (MT/s), DDR5 starts with 3,200 MT/s and can be scaled up to 6,400 MT/s.
Compared to DDR4-3200 RAM, DDR5-3200 will provide 36% more bandwidth. Higher speed DDR5 (4800 Mhz) will be twice faster than what DDR4 has to offer.
2. Low Operating Voltage
The DRAM and buffer chip registering clock driver in DDR5 use 1.1 Volt, whereas DDR4 operates at 1.2 Volt. The decrease in operating voltage is crucial, especially for battery-powered devices, such as smartphones and tablets.
3. New Power and Channel Architecture
In DDR5 RAM, the power management has been moved from the motherboard to the dual in-line memory module (DIMM) itself. The 12-Volt power management IC distributes the 1.1-Volt operating voltage supply, improving the granularity of system power loading.
The channel architecture has also been changed. While DDR4 buffer chips have a 72-bit bus containing 64 data bits and 8 ECC (error-correcting code) bits, DDR5 DIMMs support two 40-bit channels, each comprising of 32 data bits and 8 ECC bits.
Although both memories have the same data width (64-bits total), the two smaller independent channels in DDR5 enhances memory access efficiency.
More specifically, each side of the DDR5 DIMM is served by an independent 40-bit wide channel. Both sides share the Registering Clock Driver (RCD) which delivers four output clocks to each side. Whereas, in DDR4, the RCD provides two output clocks to each side.
Both 40-bit channels contain 32-bit data which is further subdivided into four 8-bit lanes. The RCD provides independent clock signals to each of these lanes, thus improving signal integrity.
4. Longer Burst Lane
The burst length in DDR4 is eight. However, to increase the burst payload in DDR5, its burst length will be extended to sixteen. This will enable a single burst to access the traditional CPU cache line size (64 bytes).
5. Higher DRAM Capacity
While DDR4 can go up to 16 Gb DRAM in a single-die package, DDR5 supports up to 32 Gb DRAMs in a single-die package.
DDR5 also features one-die error-correcting code, post-package repair, error transparency mode, and read/write cyclic redundancy check modes.
When It Will Be Available?
A few tech companies have already announced their DDR5 RAM chip. SK Hynix, for example, showed its first DDR5 RAM in 2018. It can perform 5,200 megatransfers per second at 1.1 Volt. 3 months later, the company announced another chip that could perform 6400 MT/s, the highest achievable speed as per the DDR5 standard.
Micron and Samsung are also reported to be working DDR5 memory modules, however, those might not be completely standard-complaint.
There are great chances that DDR5 will first arrive in mobile devices (in the form of LPDDR5) via Micron and Samsung. They will set a benchmark for what we can expect for desktops’ variations.
Server DRAM technology transition
SK Hynix tried to predict when DDR5 will become fully mainstream. As per their estimation, 25% of all RAM market sales will be represented by DDR5 in 2020, and 44% by the end of 2021.
However, these are just predicted figures. To be usable in laptops and desktops, the integrated controllers of AMD’s and Intel’s CPU will have to support it, and as of January 2020, none of these companies have announced any kind of support for DDR5.
Though Intel’s Sapphire Rapids CPU microarchitecture will reportedly support DDR5 SDRAM. Complications with the 7 nm and 10 nm fabrication process may push back its releases to 2021 at the earliest. AMD’s third-generation Epyc CPUs, on the other hand, will still use DDR4.
Is It Worth Buying?
There is a general assumption that existing DDR4 chips will be eventually migrated to DDR5. But the main question is: is it worth upgrading.
When DDR4 was first released, it only managed to achieve 2,133 MT/s. The fastest DDR3 chips of the time also offered 2,133 MT/s, and because of their lower latency and far tighter timings, they performed better than DDR4.
So it’s reasonable to presume that the initial DDR5 offering won’t deliver as good results as the fastest DDR4 chips available today. However, unlike DDR5, DDR4 won’t continue to improve, so gradually DDR5 will pull away.
We recommend you to wait until 2021. It will be interesting to see what kind of real-world improvements this new rapid memory can bring.