Samsung Unveils First High-K Metal Gate 512GB DDR5, at up to 7200Mbps
Samsung has announced a new 512GB DDR5 module, capable of transfer rates of up to 7200Mbps and built using high-k metal gate technology. Some of you may remember discussions of HKMG from some years ago, when Intel introduced the technology for CPUs, or again during the 28nm/32nm era, when it was discussed as part of the gate-first / gate-last debate.
Switching to a high-k dielectric means Samsung has adopted a new material replacement for the silicon dioxide gate dielectric it previously used. This new material — Intel used hafnium in 2007 — has a higher dielectric constant (k) value than the silicon dioxide Samsung likely used previously, which means it leaks less current at the same thickness.
We saw this technology deployed in logic chips first, but as process geometries have shrunk, it’s become useful to the DRAM industry as well.
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 mainstream desktop memory.
DDR5 support is expected to be introduced with Intel’s Sapphire Rapids platform, which ought to arrive in 2022. We could see some prototype systems with DDR5 and Intel’s Alder Lake — the company might design its next-gen chip to support both DDR4 and DDR5. Any AMD platform refresh this year is also likely to use DDR4. DDR5 refreshes for consumer hardware and new platforms (LGA1700 for Intel and an expected AM5 for AMD) will probably arrive in 2022 as well.
DDR5, when it arrives, is expected to kick off at DDR5-4800 — 1.5x the bandwidth of high-end DDR4 — and then scale upwards from there, with speeds as high as DDR5-8400 theoretically possible, once memory manufacturers get some time with the standard. This is a departure from previous DDR transitions, where the new standard launched at the old standard’s bandwidth. 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 latency-bound, so it’ll be interesting to see if the larger bandwidth gap between DDR4 and DDR5 at launch produces a meaningful performance gap outside of memory-sensitive benchmarks.
Integrated graphics, on the other hand, will always benefit from more memory bandwidth. Dual-channel DDR5-8400 would deliver the equivalent of 134.4GB/s of memory bandwidth to an integrated solution, and we look forward to having it.