Each NAND chip on an SSD is actually relatively slow. To get high read and write speeds, the access is multiplexed across all of the chips in the drive. Small capacity drives have a smaller number of NAND chips. This reduces the performance of the drives. In addition each NAND cell has a very limited number of lifetime writes it supports, typically 1k to 4k erase/write cycles. So drives do wear leveling, spreading writes over the whole drive. Therefore drives uses in extremely right heavy enterprise workloads may need to be very large just to support the required write endurance.
From what I understand Optane is fast enough to not need this extra controller processing. Resulting in the incrediblly latency performance demonstrated by Optabe drives. I suspect if Intel wanted to sacrifice latency, they could dramatically increase top line read and write performance by performing the same read and write interleaving that NAND SSDs do.
Intel's Optane SSDs do stripe across the controller's seven channels; that's the main reason why they're faster than the single-channel Optane Memory M.2 modules.
At any capacity or channel configuration, 3D XPoint devices benefit from not having to perform large block erase operations. They can perform reads and writes at the same granularity, allowing for in-place modification of data instead of requiring a log structure with garbage collection under the hood.
Yeah, DRAM chips are the only ones that currently offer the right balance of performance and capacity per die. NAND and 3D XPoint dies are too big and too slow per die for this use case, so they're better used as nonvolatile storage to flush the log to in the event of power failure, not as the primary log storage media.
I expect it will soon become common for high-end enterprise NVMe SSDs to include a few GB of DRAM accessible through the new Persistent Memory Region feature, so that they can be accessed through simple PCIe memory read and write operations, but will automatically be preserved by the SSD in the event of a power failure. It won't be as fast as a NVDIMM, but works with existing form factors and platforms.
Battery backed DRAM is likely a better choice for performance & endurance in most applications, as the Optane product line is a lame duck with memory that dies around the 1TB of writes mark, leaving you with lost data and a dead SSD.
There's nothing fair about making up a number that's wrong by multiple orders of magnitude.
I'm not a fan of the end of life behavior of Intel SSDs either, but it's a consistent policy that does work well for enterprise usage scenarios, with no unexpected data loss. They probably shouldn't be applying the same policy to the consumer products. But the fact that there are valid criticisms to be made doesn't mean this particular one was fair or germane.
Oh, I wasn't even looking at the value of the number. Yeah, it's bad to exaggerate like that without being clear about it. But something performance-heavy can burn out an endurance of 10 drive writes per day pretty fast.
