From a quick skim, you could think of this as roughly equivalent to shoving a large amount of DDR4 on a PCIe card and using it as a swap space. It's more sophisticated (see CXL protocol), but that gives you an idea of the tradeoffs. It seems there is some OS-level support for moving hot/cold pages between the main fast DRAM and the expansion higher latency DRAM.
It's a very valid point that DRAM has a fairly long lifetime and contains significant embedded carbon emissions, as well as the current availability crisis of new DRAM.
"Second, memory dominates the carbon footprint of
the fleet [8], accounting for 69% of CO2 emissions and posing
a significant sustainability challenge [4]. DRAM dominates
datacenter embodied CO2 largely because it is ubiquitous
and deployed in large quantities across essentially all servers.
Based on our internal fleet data, and aligned with studies
from other hyperscalers such as Microsoft [33], memory is
one of the largest single embodied-emissions contributors"
[8] U. Gupta, M. Elgamal, G. Hills, G.-Y. Wei, H.-H. S. Lee, D. Brooks,
and C.-J. Wu, “ACT: Designing Sustainable Computer Systems with an
Architectural Carbon Modeling Tool,” in Proceedings of the 49th Annual
International Symposium on Computer Architecture (ISCA’22), 2022.
[4] D. Azevedo, M. Patterson, J. Pouchet, and R. Tipley, “Carbon usage
effectiveness (cue): A green grid data center sustainability metric,” White
paper, vol. 32, 2010.
[33] J. Wang, D. S. Berger, F. Kazhamiaka, C. Irvene, C. Zhang, E. Choukse,
K. Frost, R. Fonseca, B. Warrier, C. Bansal, J. Stern, R. Bianchini,
and A. Sriraman, “Designing Cloud Servers for Lower Carbon,” in
Proceedings of the 51st Annual International Symposium on Computer
Architecture, ser. ISCA ’24, 2025, p. 452–470.
Not a reference, but I found https://www.interface-eu.org/publications/semiconductor-emis... which goes into great detail on the subject. I hadn't realized there were significant emissions of fluorinated gases directly from the fabs, which is mildly alarming. Although it looks like there has been a crackdown on this either politically or through ESG policies.
this is insightful to me as well, I'm glad to know modern memory is less polluting in use but now I wonder about how it compares to the manufacturing process
That's just El Reg being El Reg (the Zuck-buck rhyme was apparently too good to pass up). But it's a far cry from their glory days, when they coined nicknames like "The Beast of Redmond" for Microsoft or "Chipzilla" for Intel...
From a quick skim, you could think of this as roughly equivalent to shoving a large amount of DDR4 on a PCIe card and using it as a swap space. It's more sophisticated (see CXL protocol), but that gives you an idea of the tradeoffs. It seems there is some OS-level support for moving hot/cold pages between the main fast DRAM and the expansion higher latency DRAM.
It's a very valid point that DRAM has a fairly long lifetime and contains significant embedded carbon emissions, as well as the current availability crisis of new DRAM.