[bserge]

On SSDs? 32 is way off, the Samsung 470 had 256MB RAM cache and the 860 Pro a whopping 4GB for the top model.

Although they started removing it entirely for NVMe SSDs, I guess the direct transfer speed is enough to not need a cache at all.

[wtallis]

The DRAM you're referring to is for the most part not a write cache for user data. Most of that DRAM is a read cache for the FTL's logical to physical address mapping table. When the FTL is working with the typical granularity of 4kB, you get a requirement of approximately 1GB of DRAM per 1TB of NAND.

Drives that include less than this amount of DRAM show reduced performance, usually in the form of lower random read performance because the physical address of the requested data cannot be quickly found by consulting a table in DRAM and must be located by first performing at least one slow NAND read.

[mastax]

NVMe drives can access system memory over the PCIe bus.