Re: PCIe connectivity should be the lede, not NVMe
"Getting HDDs OFF OF SATA III (6Gbps) is the key to allowing them to be faster."
HDD's are still limited by how fast the bits go under the read/write heads. Only 1 head is used to read or write at a time, which I assume is down to tracking tolerances.
Modern HDD's are nano-precision marvels! I have some 7200rpm drives that max out at around 240MB/s on the outer tracks, that's 2MB on a track about 250mm long, so 8 bytes/micron, 64 bits/micron, so bits are about 16nm long. Inner tracks are half the length, so a mean of 1.5MB per track. 1TB per platter side suggests around 670,000 tracks, spanning a sweep of about 20mm, or 33.5 tracks/micron, or about 30nm apart. It's working at similar scales to transistors on modern chips (which aren't as small as 2 or 3 or 5 or 7 nm that process names might suggest), which require some rather expensive equipment to make.