Micron Samples 256 GB DDR5-8800 MCR DIMMs: Modules for Servers

https://www.anandtech.com/show/21320/micron-samples-256-gb-ddr58800-mcr-dimms-massive-modules-for-massive-servers

by mfiguiere • 2 years ago

99 27 2 years ago

anandtech.com

amelius• 2 years ago

With error correction?

kencausey• 2 years ago

It is little better than speculation but the photo shown suggests 9 bits.

wtallis6• 2 years ago

5 columns of chips on each side indicates an extra 8 bits for each 32-bit subchannel, which is pretty common for DDR5 RDIMMs. But the article mentions a 72-bit interface (the standard for DDR5 ECC UDIMMs and earlier ECC DIMM standards) rather than an 80-bit interface, so there's at least some cause for doubt about which level of ECC these modules provide.

wtallis6• 2 years ago

When's the last time anyone made non-ECC registered or buffered memory modules?

csande17• 2 years ago

ECC memory still isn't standard on consumer PCs, I don't think — although all DDR5 memory includes some error correction, manufacturers suggest it's not as robust (https://www.corsair.com/us/en/explorer/diy-builder/memory/is...).

vondur• 2 years ago

Wow. 8800 is fast DDR 5. I just ordered some Dell PCs with DDR5 4800.

wmf5• 2 years ago

It's kind of putting two channels on one DIMM so it's exactly double the speed. This DIMM is interleaving 4400 chips.

Dylan168074• 2 years ago

If I'm doing my math right, each RAM chip only has two data pins attached to it. So you could cut the number of RAM chips in half (or even fewer) and still keep the same throughput.

In other words, these same ultra-fast buffer chips could be added to an otherwise normal module. Or you could put the transceivers from them into normal RAM chips. Having so many chips is for capacity reasons, not speed reasons. There's no need to have more "channels".

martinpw• 2 years ago

How does feature size and scaling of memory compare with logic? It looks like leading edge memory is made by three companies - Samsung, Hynix and Micron - no TSMC. Do they use EUV? Do they use ASML machines?

wmf5• 2 years ago

It's hard to tell because DRAM vendors talk about things like "1x nm" or "1a nm" but it sounds like they are still above 10 nm which is fairly far behind logic processes. DRAM typically sells for much cheaper than logic so they may not be able to invest as much as TSMC.

wtallis6• 2 years ago

Yes, they're adopting EUV for DRAM processes:

https://semiconductor.samsung.com/news-events/news/samsung-a...

https://www.anandtech.com/show/18866/micron-to-bring-euv-to-...

boojums• 2 years ago

DRAM/NAND processes are optimized for different things than logic, so there isn't much cross application. My understanding is that it would be hard to make a general compute chip with a DRAM process due to a low number of metal layers, transistor types, etc. Micron [1] and Samsung have both investigated doing massively parallel compute in the memory cell, but the technology never panned out.

Regarding EUV, according to Micron's most recent quarterly report (March 20th) [2]

"We continue to mature our production capability with extreme ultraviolet lithography (EUV), and have achieved equivalent yield and quality on our 1α as well as 1ß nodes between EUV and non-EUV flows. We have begun 1γ (1-gamma) DRAM pilot production using EUV and are on track for volume production in calendar 2025."

[1] https://investors.micron.com/news-releases/news-release-deta...

[2] https://investors.micron.com/static-files/1a8d6c22-3b89-4806...

samcheng2• 2 years ago

What about Apple's M-series chips, which have on-die RAM? Is that RAM significantly more expensive per GB due to the more expensive process?

(It's certainly exorbitantly expensive for retail consumers at $200 for an 8 GB RAM upgrade on a Macbook!)

Micron Samples 256 GB DDR5-8800 MCR DIMMs: Modules for Servers

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