I guess it depends where the nand is sourced right? Some big multi year nand supply contract might allow for some cheap stuff, I think.
Obviously, MS is going to get better pricing through high-volume orders and cutting out some intermediaries, but that only gets you so far...
I still don't see how they can afford to deliver storage performance on par with the current round of PCIe 4.0 NVMe drives.
Oh, and will PCI-e gen4 require more or less ram to reach high sustained speeds?
Generally speaking, DRAM-less SSDs are slower. And, usually, you need more/larger buffers to accommodate higher speeds, whether we're talking about networking, storage, or probably a range of other things.
Here's an in-depth review of a DRAM-less NVMe SSD that supports Host Memory Buffering.
So, it's not pretty. However, I didn't read the whole review to see whether they found a way to control for the NAND speed. The second page analyzes the effect of disabling the host memory buffer, but I don't know if they found any way to compare it with a comparable drive that
does include onboard DRAM.