Those numbers seem awfully pessimistic for NAND and too optimistic for DRAM. 1ms is what you get from a fast HDD. SATA SSDs usually manage 100µs and NVMe usually has 10µs or less latency (as low as 2.8µs). DDR4-3600 usually has around 10ns CAS latency which only measures the time needed to read data from a DRAM cell but doesn't consider how much time it takes for that data to travel to a CPU. Before a CPU looks up data it has to first check the L1, L2, L3 caches which can take 30ns and then another 20ns for the memory controller to process the DRAM request. So it's 60ns (10+30+20) for a main memory access.

The difference between 10µs and 60ns is merely a factor of 167 not 1 million.

The only take away I have from your comment is that you somehow confused DRAM with the L1 cache and SSDs with HDDs. That's the only way one could possibly arrive at your numbers.

I have used rounded numbers for illustrative purposes. They might be off by 30% or more but they are within the right order of magnitude.