Samsung has announced a new 512 GB DDR5 module, capable of transfer speeds of up to 7200 Mbps and built using high-k metal gate technology. Some of you may remember discussions about HKMG a few years ago, when Intel introduced the technology for CPUs, or again below 28 nm / 32 nm, when it was discussed as part of the street-first / street-last debate.
Switching to a high-k dielectric means that Samsung has adopted a new replacement for the silicon dioxide port dielectric it previously used. This new material – Intel used hafnium in 2007 – has a higher dielectric constant (k) value than the silicon dioxide Samsung has probably used in the past, which means that less current of the same thickness leaks.
We first saw this technology implemented in logical chips, but as process geometries have shrunk, it has also become useful to the DRAM industry.
According to Samsung, these new HKMG modules use 13 percent less power than they would otherwise. Samsung first debuted HKMG in GDDR6 back in 2018, but this is the first time we’ve seen the technology in regular desktop memory.
DDR5 support is expected to be introduced with Intel’s Sapphire Rapids platform, which should arrive in 2022. We could see some prototype systems with DDR5 and Intel’s Alder Lake – the company can design its next generation chip to support both DDR4 and DDR5. Any update to the AMD platform this year is likely to use DDR4 as well. DDR5 will be updated for consumer hardware and new platforms (LGA1700 for Intel and an expected AM5 for AMD) will probably also come in 2022.
When it arrives, DDR5 is expected to start with DDR5-4800 – 1.5 times the bandwidth of high-end DDR4 – and then scale upwards from there, at speeds as high as DDR5-8400 theoretically possible, when memory manufacturers get some time with the standard. This is a departure from previous DDR transitions, where the new standard was launched with the old standard’s bandwidth. You can buy DDR3-2400, but the highest JEDEC-approved watch was DDR3-1600, and that was where DDR4 started. Desktop processors are not highly latency-bound, so it will be interesting to see if the larger bandwidth gap between DDR4 and DDR5 at launch provides a meaningful performance gap outside of memory-sensitive references.
Integrated graphics, on the other hand, will always benefit from more memory bandwidth. The dual-channel DDR5-8400 will deliver the equivalent of 134.4 GB / s of memory bandwidth for an integrated solution, and we look forward to having it.