While Intel has yet to detail its upcoming Cascade Lake processors for servers, some of the key characteristics are beginning to emerge. According to a new report from ServeTheHome, some of the new chips will support up to 3.84 TB of memory per socket, double the amount supported by contemporary Skylake-based Xeon Platinum M-series CPUs that support 1.5 TB of DDR4, due to combining 512 GB Optane DIMMs and 128GB DDR4 DIMMs. For a dual socket system, this rises to up to 7.68 TB per node.

Last year Intel published a picture of a Cascade Lake-based server outfitted with six DDR4 DIMMs and six Optane Persistent Memory DIMMs per socket. Intel’s code-named Apache Pass modules have 512 GB capacity, whereas commercial standard DDR4 LRDIMMs often carry a peak of 128 GB of usable memory. If these modules are installed into a server, in a 6 x Optane and 6 x DDR4 configuration, they will provide 3072 GB of 3D XPoint memory and 768 GB of DDR4 RAM for a total of 3.84 TB of memory.

For write endurance reasons, six DDR4 DIMMs and six Optane DIMMs per socket will likely be a popular configuration for servers that run databases which benefit from high capacity of memory.

These metrics are confirmed by a document released by QCT and their QCT QuantaMesh systems, with the key picture here below:

The top left is a single server in a 1U configuration, showing five PCIe expansion slots and up to 7.68 TB memory capacity when a Cascade Lake CPU is installed. The bottom right is the T42D-2U, giving four nodes in a 2U configuration, totalling 30 TB memory capacity for a 2U rack. Given that the price of a single DDR4 128GB LRDIMM is circa $3500, and pricing for Optane still unknown, along with reports that pricing for Cascade Lake might be adjusted, these systems are likely to cost a pretty penny.

It is worth noting, given Intel's historic policy on product segmentation, that not all Cascade Lake SKUs will support the maximum 3.84 TB of memory, leaving it only to premium models. Or Intel may go even further, potentially, and say that not all SKUs will support Optane DIMMs - that might also be a premium feature. Intel did not confirm at the launch of Optane if all of the Cascade Lake Xeons would support it (the official response was 'we haven't released that information yet').

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Source: ServeTheHome