What the OP didn't show was the integral of response times for an average set of read accesses, e.g. The typical expected waiting time. With a latency differenc

What the OP didn't show was the integral of response times for an average set of read accesses, e.g. The typical expected waiting time. With a latency difference of 1/50k second vs 1/100 second, even 1 on 500 queries missing the cache will double the latency. I'll consider the stats in the article, but rather as a means of fine-tuning between storage classes that are more similar, say high-end PCIe ssds vs cheap and large consumer ssds. Assuming the tiered storage controller is completely transparent and performs perfectly, that is.