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