Nvidia addressed some of these questions in their justification for choosing LPDDR5X for use with their Grace CPU:
Compared to an eight-channel DDR5 design, the NVIDIA Grace CPU LPDDR5X memory subsystem provides up to 53% more bandwidth at one-eighth the power per gigabyte per second while being similar in cost. An HBM2e memory subsystem would have provided substantial memory bandwidth and good energy efficiency but at more than 3x the cost-per-gigabyte and only one-eighth the maximum capacity available with LPDDR5X.
https://developer.nvidia.com/blog/nvidia-grace-cpu-superchip-architecture-in-depth/
Note that I think they're comparing on-package LPDDR5X-7400 against DDR5-4800 DIMMs, which is how they get they 53% figure and such a large energy savings.
NAND-based NVMe drives are already fast enough, with access latencies typically in the single or low double-digit microseconds. Whatever you're "feeling" isn't so much the storage device, but whatever overhead the OS and antivirus are adding. Or, maybe the app is doing more computation than you expect.
Nvidia addressed some of these questions in their justification for choosing LPDDR5X for use with their Grace CPU:
Compared to an eight-channel DDR5 design, the NVIDIA Grace CPU LPDDR5X memory subsystem provides up to 53% more bandwidth at one-eighth the power per gigabyte per second while being similar in cost. An HBM2e memory subsystem would have provided substantial memory bandwidth and good energy efficiency but at more than 3x the cost-per-gigabyte and only one-eighth the maximum capacity available with LPDDR5X.
Note that I think they're comparing on-package LPDDR5X-7400 against DDR5-4800 DIMMs, which is how they get they 53% figure and such a large energy savings.
Thanks, at least it give a ballpark idea, which I didn’t have : thanks very much for that

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NAND-based NVMe drives are already fast enough, with access latencies typically in the single or low double-digit microseconds. Whatever you're "feeling" isn't so much the storage device, but whatever overhead the OS and antivirus are adding. Or, maybe the app is doing more computation than you expect.
First I would like to say that I am not a specialist, and I am not an English native so my wording below may not be fully accurate. My apologies for that.
Even though I would agree there is overhead from the « file system », Flash Nand memory die (media) does have quite a lot of latency (micro-second), and plugged on PCI lane (NOT memory lane), and is block accessible (and not byte accessible)
When Intel was selling Persistent Optane memory, it was possible to buy it on a special Persistent DRAM Module, or as a SSD and the latency of the Optane « memory die » (media) is I think in the 100 of nanoseconds
With the Optane Persistent DRAM Module, plugged on the memory channel, it is then possible to emulate a virtual Disk (a RAMDisk), but a Persistent RAMdisk (which sadly was not bootable, I would because UEFI wasn’t design to take this possibility into account).
Even with the overhead of the File System, I think it was much faster to launch a software from the Persistent RAMdisk thanks to both lower latency of DRAM channel, and the Optane media itself (I think I watched a Youtube video from Linus on that, sorry I don’t have the link here).
One step further would be to optimize the Operating System to be « Persistent memory aware » for « Direct Access », and I would think for attempting to lower / eliminate the overhead from the File System : This would further decrease the latency…
So I would think that with Persistent Memory (ideally something like VCMA MRAM HBM stack) + Operating System optimizations, loading most softwares would feel near instantaneous (« always-on »), but then yes, I think you are right processing big data files (ex: video files) would still require time due to the processing capabilities…
My belief is that the advent of « Persistent Memory » would be disruptive and is a much, much needed technology (especially in IoT)to enable VERY big improvements in the way IT system are designed (related to « Normally-Off computing »).
It is a bit like how OLED technology is a key enabler in display technology (self emitting diode, that also allow to create flexible, rollable,… displays and open new opportunities).